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GTU Mathematics 1 (3110014) Semester 1 Summer 2026 Solved Paper

Worked solutions and paper analysis for GTU Mathematics - 1 (Subject Code: 3110014) Bachelor of Engineering Semester 1 Summer 2026 examination.

Introduction

This document provides the examination analysis and question paper layout for Gujarat Technological University (GTU) Bachelor of Engineering Semester 1, Subject: Mathematics - 1 (Subject Code: 3110014), scheduled for Summer 2026 (Exam Date: 13/07/2026). The paper structure carries a total of 70 marks distributed over five compulsory questions with internal choice options following GTU standard blueprint guidelines (3, 4, and 7 marks structure).

Paper Information

University: Gujarat Technological University
Department: Bachelor of Engineering
Semester: 1
Subject: Mathematics - 1
Subject Code: 3110014
Exam: Summer
Year: 2026

Questions and Solutions

Q.1 (a)

Question

(a) [Question text not present in source paper] (03 Marks)

Solution

Note on Question Content

The supplied paper text contains the question designation and mark allocation (3 Marks), but the question statement was omitted in the source paper template. Please consult the official GTU question bank or departmental portal for the full text of this problem.

Q.1 (b)

Question

(b) [Question text not present in source paper] (04 Marks)

Solution

Note on Question Content

The supplied paper text contains the question designation and mark allocation (4 Marks), but the question statement was omitted in the source paper template. Please consult the official GTU question bank or departmental portal for the full text of this problem.

Q.1 (c)

Question

Solution

Note on Question Content

The supplied paper text contains the question designation and mark allocation (7 Marks), but the question statement was omitted in the source paper template. Please consult the official GTU question bank or departmental portal for the full text of this problem.

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Frequently Asked Questions

What is the structure of the GTU Mathematics - 1 (3110014) examination?

The paper consists of 5 main questions carrying 14 marks each, totaling 70 marks. Each question typically contains sub-questions divided into (a) 3 marks, (b) 4 marks, and (c) 7 marks, with internal choices provided in Questions 2, 3, 4, and 5.

Are scientific calculators permitted in the GTU Mathematics - 1 exam?

Yes, simple and non-programmable scientific calculators (e.g., fx-82MS, fx-991ES Plus, or fx-991EX) are permitted as per GTU standard examination instructions.

What are the core topics covered in GTU Mathematics - 1 (3110014)?

The syllabus covers Indeterminate Forms and L'Hopital's Rule, Improper Integrals, Gamma and Beta Functions, Sequences and Infinite Series, Taylor and Maclaurin Series, Partial Derivatives, Euler's Theorem, Maxima and Minima of Functions of Several Variables, Multiple Integrals, and Matrices (including Rank, Eigenvalues, and Eigenvectors).

GTU Mathematics 1 (3110014) Semester 1 Summer 2025 Solved Paper

Complete worked solutions for GTU Mathematics - 1 (3110014) Summer 2025 examination. Step-by-step answers prepared in student-friendly plain text format.

Introduction

This document contains fully worked, step-by-step solutions for the Gujarat Technological University (GTU) Mathematics - 1 (Subject Code: 3110014) Semester 1 & 2 Examination held in Summer 2025. Every question and its sub-questions are answered comprehensively according to the allotted marks, following the official GTU syllabus guidelines.

Paper Information

University: Gujarat Technological University
Department: First Year Engineering
Semester: 1
Subject: Mathematics - 1
Subject Code: 3110014
Exam: Summer 2025
Year: 2025

Questions and Solutions

Q.1 (a)

Question

Evaluate: lim (x -> 0) [x^(-2) - cosec^2 x].

Solution

Problem Statement

Evaluate the limit: L = lim (x -> 0) [1/x^2 - cosec^2(x)]

Step 1: Identify the Indeterminate Form

Rewrite the expression using standard trigonometric functions: L = lim (x -> 0) [1/x^2 - 1/sin^2(x)]

As x -> 0, 1/x^2 -> infinity and 1/sin^2(x) -> infinity, which gives the indeterminate form (infinity - infinity).

Step 2: Combine into a Single Fraction

Combine over a common denominator: L = lim (x -> 0) [(sin^2(x) - x^2) / (x^2 * sin^2(x))]

Notice that lim (x -> 0) [sin(x)/x] = 1, so: x^2 sin^2(x) = x^4 (sin(x)/x)^2

Therefore, we can replace the denominator with x^4: L = lim (x -> 0) [(sin^2(x) - x^2) / x^4]

This is now of the form 0/0.

Step 3: Expand sin(x) using Taylor Series

The Taylor series expansion of sin(x) near x = 0 is: sin(x) = x - x^3/6 + x^5/120 - ...

Squaring both sides: sin^2(x) = [x - x^3/6 + O(x^5)]^2 sin^2(x) = x^2 - 2 x (x^3/6) + O(x^6) sin^2(x) = x^2 - x^4/3 + O(x^6)

Step 4: Substitute and Evaluate the Limit

Substitute this expansion back into the numerator: sin^2(x) - x^2 = (x^2 - x^4/3 + O(x^6)) - x^2 = -x^4/3 + O(x^6)

Now divide by x^4: L = lim (x -> 0) [(-x^4/3 + O(x^6)) / x^4] L = lim (x -> 0) [-1/3 + O(x^2)] L = -1/3

Final Answer

lim (x -> 0) [x^(-2) - cosec^2 x] = -1/3

Q.1 (b)

Question

Check the consistency of the system of linear equations. Solve it if consistent. 3x + y - 3z = 13, 2x - 3y + 7z = 5, 2x + 19y - 47z = 32.

Solution

1. Matrix Representation

The given system of linear equations is:

3x + y - 3z = 13
2x - 3y + 7z = 5
2x + 19y - 47z = 32

In matrix form, A X = B, where: A = [3, 1, -3] [2, -3, 7] [2, 19, -47]

X = [x] [y] [z]

B = [13] [ 5] [32]

The augmented matrix [A | B] is: [ 3 1 -3 | 13 ] [ 2 -3 7 | 5 ] [ 2 19 -47 | 32 ]

2. Row Reduction to Echelon Form

Make the leading entry of R1 equal to 1 using R1 -> R1 - R2: [ 1 4 -10 | 8 ] [ 2 -3 7 | 5 ] [ 2 19 -47 | 32 ]

Eliminate x from Row 2 and Row 3:

Perform R2 -> R2 - 2*R1:

R2 = [2 - 2(1), -3 - 2(4), 7 - 2(-10) | 5 - 2(8)] R2 = [0, -11, 27 | -11]

Perform R3 -> R3 - 2*R1:

R3 = [2 - 2(1), 19 - 2(4), -47 - 2(-10) | 32 - 2(8)] R3 = [0, 11, -27 | 16]

The matrix is now: [ 1 4 -10 | 8 ] [ 0 -11 27 | -11 ] [ 0 11 -27 | 16 ]

Eliminate y from Row 3:

Perform R3 -> R3 + R2:

R3 = [0 + 0, 11 + (-11), -27 + 27 | 16 + (-11)] R3 = [0, 0, 0 | 5]

The reduced matrix is: [ 1 4 -10 | 8 ] [ 0 -11 27 | -11 ] [ 0 0 0 | 5 ]

3. Consistency Check

Rank of coefficient matrix A: rank(A) = 2 (number of non-zero rows in A is 2).
Rank of augmented matrix [A | B]: rank([A | B]) = 3 (number of non-zero rows in [A | B] is 3, because row 3 has entry 5).

Since rank(A) != rank([A | B]) (2 != 3), the system is inconsistent.

Final Answer

The system of equations is inconsistent and has no solution.

Q.1 (c)

Question

Find the Fourier Series of the function f(x) = x^2 in the interval (-pi, pi).

Solution

1. Definition and Symmetry Analysis

The interval is (-pi, pi), so the half-period is L = pi. The given function is f(x) = x^2.

Check for symmetry: f(-x) = (-x)^2 = x^2 = f(x) Since f(-x) = f(x), f(x) is an even function.

For an even function on (-pi, pi):

bn = 0 for all n >= 1.
The Fourier series consists only of cosine terms:

f(x) = a0/2 + sum_{n=1}^infinity [an * cos(nx)]

2. Calculate Fourier Coefficient a0

a0 = (2/pi) integral from 0 to pi of x^2 dx a0 = (2/pi) [x^3 / 3] from 0 to pi a0 = (2/pi) [pi^3 / 3] a0 = 2pi^2 / 3

Therefore: a0 / 2 = pi^2 / 3

3. Calculate Fourier Coefficient an

an = (2/pi) integral from 0 to pi of [x^2 cos(nx)] dx

Apply integration by parts using the generalized formula (Bernoulli's rule): integral [u v] dx = u v1 - u' v2 + u'' v3 - ... Let: u = x^2 ==> u' = 2x ==> u'' = 2 ==> u''' = 0 v = cos(nx) ==> v1 = sin(nx)/n ==> v2 = -cos(nx)/n^2 ==> v3 = -sin(nx)/n^3

Evaluating the integral: an = (2/pi) [ x^2 (sin(nx)/n) - 2x (-cos(nx)/n^2) + 2 (-sin(nx)/n^3) ] from 0 to pi an = (2/pi) [ (x^2 sin(nx)/n) + (2x cos(nx)/n^2) - (2 sin(nx)/n^3) ] from 0 to pi

Substitute the limits:

At x = pi: sin(npi) = 0 and cos(npi) = (-1)^n
At x = 0: all terms vanish because sin(0) = 0 and x = 0

an = (2/pi) [ 0 + (2pi (-1)^n / n^2) - 0 ] an = (2/pi) [ 2pi (-1)^n / n^2 ] an = 4 * (-1)^n / n^2

4. Write the Complete Fourier Series

Substitute a0/2 and an into the Fourier series expansion: f(x) = pi^2 / 3 + sum_{n=1}^infinity [ 4 (-1)^n / n^2 cos(nx) ]

Expanding the first few terms: x^2 = pi^2/3 - 4 * [ cos(x)/1^2 - cos(2x)/2^2 + cos(3x)/3^2 - cos(4x)/4^2 + ... ]

Final Answer

f(x) = pi^2/3 + 4 sum_{n=1}^infinity [ ((-1)^n / n^2) cos(nx) ]

Q.2 (a)

Question

Define the improper integrals of the first kind and the second kind. State the relation between Beta and Gamma function.

Solution

1. Improper Integral of the First Kind

An improper integral of the first kind is a definite integral where at least one of the integration limits is infinite, while the integrand f(x) remains bounded on the entire interval.

Form:
integral from a to infinity of f(x) dx, or
integral from -infinity to b of f(x) dx, or
integral from -infinity to infinity of f(x) dx.
Example: integral from 1 to infinity of (1/x^2) dx.

2. Improper Integral of the Second Kind

An improper integral of the second kind is an integral over a finite interval [a, b], where the integrand f(x) becomes unbounded (has an infinite discontinuity) at one or more points in [a, b].

Form:
integral from a to b of f(x) dx, where lim (x -> c) |f(x)| = infinity for some c in [a, b].
Example: integral from 0 to 1 of (1/sqrt(x)) dx, where the integrand becomes infinite at the lower limit x = 0.

3. Relation between Beta and Gamma Functions

The relationship connecting the Beta function B(m, n) and the Gamma function Gamma(n) is:

B(m, n) = [ Gamma(m) * Gamma(n) ] / Gamma(m + n)

Where m > 0 and n > 0.

Q.2 (b)

Question

Find the area of the surface of revolution generated by revolving the curve x = y^3 from y = 0 to y = 2.

Solution

Given:

Curve: x = y^3
Limits: y ranges from y = 0 to y = 2
Standard revolution: revolved about the y-axis

1. Formula

The surface area S generated by revolving the curve x = g(y) about the y-axis between y = c and y = d is: S = 2 pi integral from c to d of [ x * sqrt(1 + (dx/dy)^2) ] dy

2. Compute Derivative and Arc Length Element

Given x = y^3: dx/dy = 3y^2

Compute 1 + (dx/dy)^2: 1 + (dx/dy)^2 = 1 + (3y^2)^2 = 1 + 9y^4

Thus, the arc length differential is: ds = sqrt(1 + 9y^4) dy

3. Set Up and Evaluate the Integral

S = 2 pi integral from 0 to 2 of [ y^3 * sqrt(1 + 9y^4) ] dy

Use substitution: Let u = 1 + 9y^4 du = 36y^3 dy ==> y^3 dy = du / 36

Change limits of integration:

When y = 0: u = 1 + 9(0)^4 = 1
When y = 2: u = 1 + 9(2)^4 = 1 + 9(16) = 1 + 144 = 145

Substitute u and du into the integral: S = 2 pi integral from 1 to 145 of [ sqrt(u) (du / 36) ] S = (2 pi / 36) integral from 1 to 145 of [ u^(1/2) ] du S = (pi / 18) [ (2/3) u^(3/2) ] from 1 to 145 S = (pi / 27) [ 145^(3/2) - 1^(3/2) ] S = (pi / 27) [ 145 sqrt(145) - 1 ]

(Note: If the revolution is considered about the x-axis, the formula would be S = 2piintegral ysqrt(1 + (dx/dy)^2) dy = 2piintegral_0^2 ysqrt(1 + 9y^4) dy. By standard convention in GTU calculus papers, when a function is given as x = g(y) with y-limits, revolving about the y-axis is the standard interpretation).

Final Answer

Surface Area S = (pi / 27) (145 sqrt(145) - 1) square units (approximately 203.04 square units).

Q.2 (c)

Question

Find eigen values and corresponding eigen vectors of the matrix ( 0 1 1 ) ( 1 0 1 ) ( 1 1 0 ).

Solution

1. Characteristic Equation

Let the given matrix be: A = [0 1 1] [1 0 1] [1 1 0]

Expanding the determinant: -lambda [(-lambda)(-lambda) - (1)(1)] - 1 [1(-lambda) - 11] + 1 [11 - 1(-lambda)] = 0 -lambda (lambda^2 - 1) - 1 (-lambda - 1) + 1 (1 + lambda) = 0 -lambda^3 + lambda + lambda + 1 + 1 + lambda = 0 -lambda^3 + 3lambda + 2 = 0 lambda^3 - 3*lambda - 2 = 0

2. Finding the Eigenvalues

Test for roots:

For lambda = -1: (-1)^3 - 3(-1) - 2 = -1 + 3 - 2 = 0. So lambda = -1 is a root.

Factorize (lambda + 1): lambda^3 - 3lambda - 2 = (lambda + 1)(lambda^2 - lambda - 2) = 0 (lambda + 1)(lambda + 1)(lambda - 2) = 0 (lambda + 1)^2 (lambda - 2) = 0

Therefore, the eigenvalues are: lambda1 = 2, lambda2 = -1, lambda_3 = -1

3. Eigenvector for lambda = 2

Solve (A - 2*I) X = 0: [ -2 1 1 ] [ x1 ] [ 0 ] [ 1 -2 1 ] [ x2 ] = [ 0 ] [ 1 1 -2 ] [ x3 ] [ 0 ]

From Row 1 and Row 2: -2x1 + x2 + x3 = 0 x1 - 2x2 + x3 = 0

Subtracting the second equation from the first: -3x1 + 3x2 = 0 ==> x1 = x2

Substitute x1 = x2 into the first equation: -2*x1 + x1 + x3 = 0 ==> x3 = x1

Thus, x1 = x2 = x3. Choosing x1 = 1: X_1 = [ 1 ] [ 1 ] [ 1 ]

4. Eigenvectors for Repeated Eigenvalue lambda = -1

Solve (A - (-1)*I) X = (A + I) X = 0: [ 1 1 1 ] [ x1 ] [ 0 ] [ 1 1 1 ] [ x2 ] = [ 0 ] [ 1 1 1 ] [ x3 ] [ 0 ]

All three rows are identical, giving the single linear equation: x1 + x2 + x3 = 0 ==> x1 = -x2 - x3

This system has two linearly independent free variables (x2 and x3):

Setting x2 = 1, x3 = 0:

x1 = -1 X_2 = [ -1 ] [ 1 ] [ 0 ]

Setting x2 = 0, x3 = 1:

x1 = -1 X_3 = [ -1 ] [ 0 ] [ 1 ]

Final Answer

Eigenvalues: lambda = 2, -1, -1
Eigenvectors:
For lambda = 2: X_1 = [1, 1, 1]^T
For lambda = -1: X2 = [-1, 1, 0]^T and X3 = [-1, 0, 1]^T

Q.2 (c) OR

Question

Find the inverse of the matrix using Gauss-Jordan elimination method. A = ( 1 2 3 2 3 0 0 1 2 ).

Solution

1. Setup Augmented Matrix

Set up the matrix [A | I_3]: [ 1 2 3 | 1 0 0 ] [ 2 3 0 | 0 1 0 ] [ 0 1 2 | 0 0 1 ]

2. Apply Row Operations

Step 1: Eliminate the first entry of Row 2 using R2 -> R2 - 2*R1:

R2 = [2 - 2(1), 3 - 2(2), 0 - 2(3) | 0 - 2(1), 1 - 2(0), 0 - 2(0)]
R2 = [0, -1, -6 | -2, 1, 0]

The matrix becomes: [ 1 2 3 | 1 0 0 ] [ 0 -1 -6 | -2 1 0 ] [ 0 1 2 | 0 0 1 ]

Step 2: Multiply Row 2 by -1 (R2 -> -1 * R2): [ 1 2 3 | 1 0 0 ] [ 0 1 6 | 2 -1 0 ] [ 0 1 2 | 0 0 1 ]

Step 3: Eliminate entries above and below the pivot in column 2:

R1 -> R1 - 2*R2:
R1 = [1 - 0, 2 - 2(1), 3 - 2(6) | 1 - 2(2), 0 - 2(-1), 0 - 0]
R1 = [1, 0, -9 | -3, 2, 0]

R3 -> R3 - R2:
R3 = [0 - 0, 1 - 1, 2 - 6 | 0 - 2, 0 - (-1), 1 - 0]
R3 = [0, 0, -4 | -2, 1, 1]

The matrix becomes: [ 1 0 -9 | -3 2 0 ] [ 0 1 6 | 2 -1 0 ] [ 0 0 -4 | -2 1 1 ]

Step 4: Make the pivot in Row 3 equal to 1 (R3 -> R3 / (-4)): [ 1 0 -9 | -3 2 0 ] [ 0 1 6 | 2 -1 0 ] [ 0 0 1 | 1/2 -1/4 -1/4 ]

Step 5: Eliminate entries in column 3 above the pivot:

R1 -> R1 + 9*R3:
R1_1 = -3 + 9*(1/2) = -3 + 9/2 = 3/2
R1_2 = 2 + 9*(-1/4) = 2 - 9/4 = -1/4
R1_3 = 0 + 9*(-1/4) = -9/4
R1 = [1, 0, 0 | 3/2, -1/4, -9/4]

R2 -> R2 - 6*R3:
R2_1 = 2 - 6*(1/2) = 2 - 3 = -1
R2_2 = -1 - 6*(-1/4) = -1 + 6/4 = 1/2
R2_3 = 0 - 6*(-1/4) = 6/4 = 3/2
R2 = [0, 1, 0 | -1, 1/2, 3/2]

The augmented matrix is now [I | A^(-1)]: [ 1 0 0 | 3/2 -1/4 -9/4 ] [ 0 1 0 | -1 1/2 3/2 ] [ 0 0 1 | 1/2 -1/4 -1/4 ]

Taking 1/4 as a common factor: A^(-1) = (1/4) * [ 6 -1 -9 ] [ -4 2 6 ] [ 2 -1 -1 ]

3. Verification

Multiply A by A^(-1): [1 2 3] [ 6 -1 -9 ] [ 16 + 2(-4) + 32, 1(-1) + 22 + 3(-1), 1(-9) + 26 + 3(-1) ] [2 3 0] [ -4 2 6 ] = [ 26 + 3(-4) + 0, 2(-1) + 32 + 0, 2(-9) + 36 + 0 ] [0 1 2] [ 2 -1 -1 ] [ 0 + 1(-4) + 22, 0 + 12 + 2(-1), 0 + 16 + 2(-1) ]

= [ 6 - 8 + 6, -1 + 4 - 3, -9 + 12 - 3 ] [ 4 0 0 ] [ 12 - 12 + 0, -2 + 6 + 0, -18 + 18 + 0] = [ 0 4 0 ] [ -4 + 4, 2 - 2, 6 - 2 ] [ 0 0 4 ]

Multiplying by (1/4) yields I_3. The result is confirmed.

Final Answer

A^(-1) = [ 3/2 -1/4 -9/4 ] [ -1 1/2 3/2 ] [ 1/2 -1/4 -1/4 ]

Q.3 (a)

Question

Determine whether lim ((x, y) -> (0, 0)) (x^2 - y^2) / (x^2 + y^2) exists and find it if exists.

Solution

1. Approach

To determine if the multivariable limit exists, evaluate the limit as (x, y) approaches (0, 0) along different linear paths y = m*x.

2. Path Testing

Let y = m*x, where m is the slope of the straight line path passing through the origin.

Substitute y = mx into the given expression: L = lim (x -> 0) [ (x^2 - (mx)^2) / (x^2 + (mx)^2) ] L = lim (x -> 0) [ x^2 (1 - m^2) / (x^2 * (1 + m^2)) ]

Since x != 0 as x -> 0, cancel x^2: L = (1 - m^2) / (1 + m^2)

3. Conclusion

Along the path y = 0 (x-axis, m = 0):
L = (1 - 0) / (1 + 0) = 1

Along the path x = 0 (y-axis, m -> infinity):
L = -1

Along the path y = x (m = 1):
L = (1 - 1) / (1 + 1) = 0

Since the limit depends on the slope m of the path approaching the origin, the limit is not unique.

Final Answer

The limit does not exist.

Q.3 (b)

Question

Find the equation of tangent plane and normal line to the surface 2xz^2 - 3xy - 4x = 7 at the point (1, -1, 2).

Solution

1. Define the Surface Function

Let the implicit surface be: F(x, y, z) = 2xz^2 - 3xy - 4*x - 7 = 0 Given point P = (x0, y0, z0) = (1, -1, 2).

Check that P lies on the surface: F(1, -1, 2) = 2(1)(2^2) - 3(1)(-1) - 4(1) - 7 = 8 + 3 - 4 - 7 = 0 (Confirmed).

2. Compute the Gradient Vector (Normal Vector)

The normal vector to the surface is grad F = (dF/dx) i + (dF/dy) j + (dF/dz) k.

Calculate the partial derivatives:

dF/dx = 2z^2 - 3y - 4
dF/dy = -3*x
dF/dz = 4xz

Evaluate the partial derivatives at P(1, -1, 2):

dF/dx |_(1, -1, 2) = 2(2)^2 - 3(-1) - 4 = 8 + 3 - 4 = 7
dF/dy |_(1, -1, 2) = -3*(1) = -3
dF/dz |_(1, -1, 2) = 4(1)(2) = 8

Therefore, the normal vector is: N = grad F |_(1, -1, 2) = 7 i - 3 j + 8 k

3. Equation of the Tangent Plane

The equation of the tangent plane at (x0, y0, z0) is: (dF/dx)(x - x0) + (dF/dy)(y - y0) + (dF/dz)*(z - z0) = 0

Substitute the values: 7(x - 1) + (-3)(y - (-1)) + 8(z - 2) = 0 7(x - 1) - 3(y + 1) + 8(z - 2) = 0 7x - 7 - 3y - 3 + 8z - 16 = 0 7x - 3y + 8z - 26 = 0 7x - 3y + 8z = 26

4. Equation of the Normal Line

The symmetric equation of the normal line is: (x - x0) / (dF/dx) = (y - y0) / (dF/dy) = (z - z0) / (dF/dz)

Substitute the values: (x - 1) / 7 = (y + 1) / (-3) = (z - 2) / 8

Final Answer

Tangent Plane: 7x - 3y + 8z = 26
Normal Line: (x - 1)/7 = (y + 1)/(-3) = (z - 2)/8

Q.3 (c)

Question

Find the extreme values of the function x^3 + y^3 - 63(x + y) + 12xy.

Solution

1. Given Function

f(x, y) = x^3 + y^3 - 63x - 63y + 12xy

2. Find Critical Points

Compute first-order partial derivatives: fx = df/dx = 3x^2 - 63 + 12y fy = df/dy = 3y^2 - 63 + 12x

Set fx = 0 and fy = 0:

3x^2 + 12y - 63 = 0 ==> x^2 + 4y - 21 = 0 ==> 4y = 21 - x^2
3y^2 + 12x - 63 = 0 ==> y^2 + 4x - 21 = 0 ==> 4x = 21 - y^2

Subtract equation (2) from equation (1): (x^2 - y^2) + 4(y - x) = 0 (x - y)(x + y) - 4(x - y) = 0 (x - y) * (x + y - 4) = 0

This gives two cases:

Case 1: x = y
Case 2: x + y = 4 ==> y = 4 - x

Solving Case 1: x = y

Substitute y = x into x^2 + 4y - 21 = 0: x^2 + 4x - 21 = 0 (x + 7)(x - 3) = 0 So, x = 3 or x = -7. Since y = x, we get two critical points:

Point A: (3, 3)
Point B: (-7, -7)

Solving Case 2: y = 4 - x

Substitute y = 4 - x into x^2 + 4y - 21 = 0: x^2 + 4*(4 - x) - 21 = 0 x^2 + 16 - 4x - 21 = 0 x^2 - 4x - 5 = 0 (x - 5)(x + 1) = 0 So, x = 5 or x = -1.

If x = 5: y = 4 - 5 = -1 ==> Point C: (5, -1)
If x = -1: y = 4 - (-1) = 5 ==> Point D: (-1, 5)

Thus, the four critical points are: (3, 3), (-7, -7), (5, -1), and (-1, 5).

3. Second Derivative Test

Compute the second-order partial derivatives: r = fxx = d^2f/dx^2 = 6x s = fxy = d^2f/(dx dy) = 12 t = fyy = d^2f/dy^2 = 6y

Discriminant: D = rt - s^2 = (6x)(6y) - 12^2 = 36xy - 144

Now test each critical point:

At (3, 3):

r = 6(3) = 18 > 0
D = 36(3)(3) - 144 = 324 - 144 = 180 > 0
Since D > 0 and r > 0, f has a local minimum at (3, 3).
Value: f(3, 3) = 3^3 + 3^3 - 63(3 + 3) + 12(3)(3) = 27 + 27 - 378 + 108 = -216.

At (-7, -7):

r = 6(-7) = -42 < 0
D = 36(-7)(-7) - 144 = 36(49) - 144 = 1764 - 144 = 1620 > 0
Since D > 0 and r < 0, f has a local maximum at (-7, -7).
Value: f(-7, -7) = (-7)^3 + (-7)^3 - 63(-14) + 12(49) = -343 - 343 + 882 + 588 = 784.

At (5, -1):

D = 36(5)(-1) - 144 = -180 - 144 = -324 < 0
Since D < 0, (5, -1) is a saddle point.

At (-1, 5):

D = 36(-1)(5) - 144 = -180 - 144 = -324 < 0
Since D < 0, (-1, 5) is a saddle point.

Final Answer

Local Maximum Value: 784 at (-7, -7)
Local Minimum Value: -216 at (3, 3)
Saddle Points: (5, -1) and (-1, 5)

Q.3 (a) OR

Question

State chain rule for du/dx for u = f(v, w), where v = g(x, y), w = h(x, y). If u = f(x - 2y, 2y - 3z, 3z - x) then show that du/dx + (1/2)du/dy + (1/3)du/dz = 0.

Solution

1. Statement of Chain Rule

Let u = f(v, w) be a differentiable function of two variables v and w, where v = g(x, y) and w = h(x, y) are differentiable functions of x and y. Then the partial derivative of u with respect to x is given by the chain rule:

du/dx = (du/dv) (dv/dx) + (du/dw) (dw/dx)

2. Proof of Identity

(Note: The question paper has a minor typographical print '1/3 du/dy = 0'; the standard multivariable calculus identity is du/dx + (1/2)du/dy + (1/3)du/dz = 0).

Let the intermediate variables be defined as: r = x - 2y s = 2y - 3z t = 3z - x

Thus, u = f(r, s, t).

Step 2.1: Partial derivative with respect to x du/dx = (du/dr)(dr/dx) + (du/ds)(ds/dx) + (du/dt)(dt/dx) Since dr/dx = 1, ds/dx = 0, dt/dx = -1: du/dx = (du/dr)(1) + (du/ds)(0) + (du/dt)(-1) du/dx = du/dr - du/dt --- (Equation 1)

Step 2.2: Partial derivative with respect to y du/dy = (du/dr)(dr/dy) + (du/ds)(ds/dy) + (du/dt)(dt/dy) Since dr/dy = -2, ds/dy = 2, dt/dy = 0: du/dy = (du/dr)(-2) + (du/ds)(2) + (du/dt)(0) du/dy = -2(du/dr) + 2(du/ds)

Multiply by 1/2: (1/2) * (du/dy) = -du/dr + du/ds --- (Equation 2)

Step 2.3: Partial derivative with respect to z du/dz = (du/dr)(dr/dz) + (du/ds)(ds/dz) + (du/dt)(dt/dz) Since dr/dz = 0, ds/dz = -3, dt/dz = 3: du/dz = (du/dr)(0) + (du/ds)(-3) + (du/dt)(3) du/dz = -3(du/ds) + 3(du/dt)

Multiply by 1/3: (1/3) * (du/dz) = -du/ds + du/dt --- (Equation 3)

Step 2.4: Sum the three expressions Adding Equations (1), (2), and (3): du/dx + (1/2)du/dy + (1/3)du/dz = (du/dr - du/dt) + (-du/dr + du/ds) + (-du/ds + du/dt) = (du/dr - du/dr) + (du/ds - du/ds) + (du/dt - du/dt) = 0

Hence proved.

Q.3 (b) OR

Question

Find the directional derivative of f(x, y, z) = xy^2 + yz^2 at the point (2, -1, 1) in the direction of the vector i + 2j + 2k.

Solution

1. Formula

The directional derivative of a scalar function f in the direction of a vector a is given by: Du f = grad f . ucap where:

grad f = (df/dx) i + (df/dy) j + (df/dz) k
u_cap = a / |a| is the unit vector in the direction of a.

2. Compute the Gradient of f

Given f(x, y, z) = xy^2 + yz^2:

df/dx = y^2
df/dy = 2xy + z^2
df/dz = 2yz

Evaluate grad f at the point P(2, -1, 1):

df/dx = (-1)^2 = 1
df/dy = 2(2)(-1) + (1)^2 = -4 + 1 = -3
df/dz = 2(-1)(1) = -2

Thus: grad f |_(2, -1, 1) = 1 i - 3 j - 2 k

3. Compute the Unit Vector

Given vector a = i + 2 j + 2 k. Magnitude of a: |a| = sqrt(1^2 + 2^2 + 2^2) = sqrt(1 + 4 + 4) = sqrt(9) = 3

Unit vector: u_cap = (1/3) * (i + 2 j + 2 k)

4. Calculate Directional Derivative

Du f = grad f . ucap = (1 i - 3 j - 2 k) . [(1/3) (i + 2 j + 2 k)] = (1/3) [ (1)(1) + (-3)(2) + (-2)(2) ] = (1/3) [ 1 - 6 - 4 ] = (1/3) (-9) = -3

Final Answer

The directional derivative is -3.

Q.3 (c) OR

Question

The temperature T(x, y, z) at any point in space is T = 400xy*z^2. Find the highest temperature on surface of the sphere x^2 + y^2 + z^2 = 1.

Solution

1. Method Setup (Lagrange Multipliers)

We want to maximize: T(x, y, z) = 400 x y * z^2 subject to the constraint: g(x, y, z) = x^2 + y^2 + z^2 - 1 = 0

Using the method of Lagrange multipliers: grad T = lambda * grad g

2. Form the System of Equations

Compute the gradients:

grad T = (400yz^2) i + (400xz^2) j + (800xy*z) k
grad g = (2x) i + (2y) j + (2z) k

Equating components:

400yz^2 = 2lambdax ==> 200yz^2 = lambda*x
400xz^2 = 2lambday ==> 200xz^2 = lambda*y
800xyz = 2lambdaz ==> 400xyz = lambda*z
x^2 + y^2 + z^2 = 1

3. Analyze the Equations

To maximize T, we need T > 0, so x != 0, y != 0, and z != 0.

Multiply (1) by x: lambdax^2 = 200xyz^2
Multiply (2) by y: lambday^2 = 200xyz^2
Multiply (3) by z: lambdaz^2 = 400xyz^2

Since the right-hand sides of the first two are identical and lambda != 0: lambdax^2 = lambday^2 ==> x^2 = y^2

Also, comparing lambdaz^2 with lambdax^2: lambdaz^2 = 2 (lambdax^2) ==> z^2 = 2x^2

4. Substitute into the Constraint Equation

Substitute y^2 = x^2 and z^2 = 2x^2 into x^2 + y^2 + z^2 = 1: x^2 + x^2 + 2x^2 = 1 4*x^2 = 1 x^2 = 1/4 ==> x = +- 1/2

Then: y^2 = 1/4 ==> y = +- 1/2 z^2 = 2*(1/4) = 1/2 ==> z = +- 1/sqrt(2)

5. Find the Maximum Value of T

For maximum temperature, we choose signs of x and y such that x*y > 0 (both positive or both negative):

x = 1/2, y = 1/2 (or x = -1/2, y = -1/2)
z^2 = 1/2

Substitute these into T: Tmax = 400 * (1/2) * (1/2) * (1/2) Tmax = 400 * (1/8) T_max = 50

Final Answer

The highest temperature on the surface of the sphere is 50 units.

Q.4 (a)

Question

Evaluate integral from 0 to 2 of integral from -1 to 1 of (1 - 6x^2y) dx dy.

Solution

1. Integral Setup

We are asked to evaluate the iterated double integral: I = integral (y = 0 to 2) [ integral (x = -1 to 1) (1 - 6x^2y) dx ] dy

2. Inner Integration (with respect to x)

Integrate with respect to x, treating y as a constant: inner_I = integral (x = -1 to 1) (1 - 6x^2y) dx = [ x - 6 (x^3 / 3) y ] from x = -1 to 1 = [ x - 2x^3y ] from x = -1 to 1

Substitute the limits: At x = 1: 1 - 2(1)^3y = 1 - 2y At x = -1: -1 - 2(-1)^3y = -1 + 2y

inner_I = (1 - 2y) - (-1 + 2y) = 1 - 2y + 1 - 2y = 2 - 4y

3. Outer Integration (with respect to y)

Now integrate the result with respect to y from 0 to 2: I = integral (y = 0 to 2) (2 - 4y) dy = [ 2y - 4 (y^2 / 2) ] from y = 0 to 2 = [ 2y - 2y^2 ] from y = 0 to 2

Substitute the limits: At y = 2: 2(2) - 2(2)^2 = 4 - 8 = -4 At y = 0: 2(0) - 2(0)^2 = 0

I = -4 - 0 = -4

Final Answer

The value of the integral is -4.

Q.4 (b)

Question

Find the value of double integral over R of (2x - y^2) dA over the triangular region R enclosed between the line y = -x + 1, y = x + 1 and y = 3.

Solution

1. Region Description

The bounding lines are:

y = -x + 1 ==> x = 1 - y
y = x + 1 ==> x = y - 1
y = 3

Find the vertices of the triangular region R:

Intersection of y = -x + 1 and y = x + 1:
-x + 1 = x + 1 ==> 2x = 0 ==> x = 0, y = 1. Vertex: (0, 1)
Intersection of y = -x + 1 and y = 3:
3 = -x + 1 ==> x = -2. Vertex: (-2, 3)
Intersection of y = x + 1 and y = 3:
3 = x + 1 ==> x = 2. Vertex: (2, 3)

2. Integration Limits

Since y goes from 1 to 3, for each fixed horizontal line y:

Left boundary: x = -(y - 1) = 1 - y
Right boundary: x = y - 1

Thus, the limits of integration are:

x runs from (1 - y) to (y - 1)
y runs from 1 to 3

3. Evaluate the Double Integral

I = integral (y = 1 to 3) [ integral (x = 1 - y to y - 1) (2x - y^2) dx ] dy

Inner integral with respect to x: integral (x = 1 - y to y - 1) (2x - y^2) dx = [ x^2 - y^2 * x ] from x = -(y - 1) to (y - 1)

Note that x^2 is an even function of x, so [x^2] from -(y-1) to (y-1) is 0. Specifically: = [ (y - 1)^2 - y^2(y - 1) ] - [ (-(y - 1))^2 - y^2(-(y - 1)) ] = [ (y - 1)^2 - y^2(y - 1) ] - [ (y - 1)^2 + y^2(y - 1) ] = -2 y^2 (y - 1) = -2y^3 + 2y^2

Outer integral with respect to y: I = integral (y = 1 to 3) (-2y^3 + 2y^2) dy = [ -2 (y^4 / 4) + 2 (y^3 / 3) ] from 1 to 3 = [ -y^4 / 2 + 2*y^3 / 3 ] from 1 to 3

Substitute upper limit y = 3: -3^4 / 2 + 2(3^3) / 3 = -81/2 + 2(27)/3 = -81/2 + 18 = -81/2 + 36/2 = -45/2

Substitute lower limit y = 1: -1^4 / 2 + 2*(1^3) / 3 = -1/2 + 2/3 = -3/6 + 4/6 = 1/6

Subtract: I = -45/2 - 1/6 = -135/6 - 1/6 = -136/6 = -68/3

Final Answer

The value of the integral is -68/3.

Q.4 (c)

Question

Change the order of integral and evaluate integral from 0 to 4a of integral from x^2/(4a) to 2*sqrt(ax) dy dx, (a > 0).

Solution

1. Identify the Original Limits and Curves

The given integral is: I = integral (x = 0 to 4a) [ integral (y = x^2 / (4a) to 2*sqrt(ax)) dy ] dx

Lower curve: y = x^2 / (4a) ==> x^2 = 4a*y (parabola opening upward)
Upper curve: y = 2sqrt(ax) ==> y^2 = 4ax (parabola opening to the right)

2. Find the Intersection Points

Substitute y = x^2 / (4a) into y^2 = 4ax: (x^2 / (4a))^2 = 4ax x^4 / (16a^2) = 4ax x^4 - 64a^3 x = 0 x (x^3 - 64a^3) = 0

This gives x = 0 and x = 4a.

At x = 0: y = 0 ==> (0, 0)
At x = 4a: y = (4a)^2 / (4a) = 4a ==> (4a, 4a)

3. Change the Order of Integration

In the original order, vertical strips are used (y varies from bottom parabola to top parabola, x from 0 to 4a).

To reverse the order, use horizontal strips:

y varies from 0 to 4a.
For a given y, x enters the region at the curve y^2 = 4ax (left curve) and exits at the curve x^2 = 4ay (right curve).
Left boundary: x = y^2 / (4a)
Right boundary: x = sqrt(4ay) = 2sqrt(a*y)

Therefore, with the order changed, the integral becomes: I = integral (y = 0 to 4a) [ integral (x = y^2 / (4a) to 2*sqrt(ay)) dx ] dy

4. Evaluate the Integral

Inner integral with respect to x: integral (x = y^2 / (4a) to 2sqrt(ay)) dx = [ x ] from y^2 / (4a) to 2sqrt(ay) = 2sqrt(a)y^(1/2) - y^2 / (4a)

Outer integral with respect to y: I = integral (y = 0 to 4a) [ 2sqrt(a)y^(1/2) - y^2 / (4a) ] dy = [ 2sqrt(a) (y^(3/2) / (3/2)) - (1 / (4a)) (y^3 / 3) ] from 0 to 4a = [ (4/3)sqrt(a)*y^(3/2) - y^3 / (12a) ] from 0 to 4a

Evaluate at y = 4a:

First term: (4/3)sqrt(a) (4a)^(3/2) = (4/3)sqrt(a) 8 a^(3/2) = (32/3) a^2
Second term: (4a)^3 / (12a) = 64a^3 / (12a) = (16/3) a^2

Subtract the terms: I = (32/3)a^2 - (16/3)a^2 I = (16/3) * a^2

Final Answer

After changing the order of integration, the value is (16/3) * a^2.

Q.4 (a) OR

Question

Calculate integral from 0 to 2 of integral from 0 to 1 of integral from 0 to yz of xyz dx dy dz.

Solution

1. Set Up the Triple Integral

I = integral (z = 0 to 2) [ integral (y = 0 to 1) [ integral (x = 0 to yz) (xyz) dx ] dy ] dz

2. First Integration (with respect to x)

Treat y and z as constants: inner_x = integral (x = 0 to yz) (xyz) dx = yz [ x^2 / 2 ] from x = 0 to yz = yz [ (yz)^2 / 2 - 0 ] = yz (y^2 z^2 / 2) = (1/2) y^3 * z^3

3. Second Integration (with respect to y)

Now integrate with respect to y from 0 to 1: inner_y = integral (y = 0 to 1) [ (1/2) y^3 z^3 ] dy = (1/2) z^3 [ y^4 / 4 ] from y = 0 to 1 = (1/2) z^3 (1/4 - 0) = (1/8) * z^3

4. Third Integration (with respect to z)

Now integrate with respect to z from 0 to 2: I = integral (z = 0 to 2) [ (1/8) z^3 ] dz = (1/8) [ z^4 / 4 ] from z = 0 to 2 = (1/32) [ 2^4 - 0 ] = (1/32) 16 = 1/2

Final Answer

The value of the triple integral is 1/2.

Q.4 (b) OR

Question

Evaluate integral from 0 to 1 of integral from x to 1 of sin(y^2) dy dx.

Solution

1. Observe the Given Integral

The given integral is: I = integral (x = 0 to 1) [ integral (y = x to 1) sin(y^2) dy ] dx

The integrand sin(y^2) cannot be integrated analytically with respect to y in terms of elementary functions. Therefore, we must change the order of integration.

2. Identify the Region of Integration

The limits in the given integral are:

x varies from 0 to 1
For a fixed x, y varies from the line y = x to y = 1

This describes a triangular region bounded by:

y = x
y = 1
x = 0 (the y-axis)

3. Reverse the Order of Integration

Using horizontal strips instead of vertical strips:

y varies from 0 to 1
For a given y, x varies from x = 0 to x = y

Thus, the integral becomes: I = integral (y = 0 to 1) [ integral (x = 0 to y) sin(y^2) dx ] dy

4. Evaluate the Integral

Inner integral with respect to x: integral (x = 0 to y) sin(y^2) dx = [ x sin(y^2) ] from x = 0 to y = y sin(y^2)

Outer integral with respect to y: I = integral (y = 0 to 1) y * sin(y^2) dy

Use substitution: Let u = y^2 ==> du = 2y dy ==> y dy = du / 2

When y = 0: u = 0
When y = 1: u = 1

Substitute: I = integral (u = 0 to 1) sin(u) (du / 2) = (1/2) [ -cos(u) ] from 0 to 1 = (1/2) [ -cos(1) - (-cos(0)) ] = (1/2) [ 1 - cos(1) ]

Final Answer

The value of the integral is (1 - cos(1)) / 2.

Q.4 (c) OR

Question

Compute integral from 0 to 2 of integral from 0 to sqrt(2x - x^2) of [ x / (x^2 + y^2) ] dy dx by transforming into polar coordinates.

Solution

1. Identify the Region in Cartesian Coordinates

The limits are:

y varies from 0 to sqrt(2x - x^2)
x varies from 0 to 2

The upper boundary is: y = sqrt(2x - x^2) y^2 = 2x - x^2 x^2 + y^2 - 2x = 0 (x - 1)^2 + y^2 = 1

This is the upper half of a circle of radius 1 centered at (1, 0), since y >= 0.

2. Transform into Polar Coordinates

The standard transformations are: x = r cos(theta) y = r sin(theta) x^2 + y^2 = r^2 dx dy = r dr dtheta

Transform the circle equation: x^2 + y^2 = 2x ==> r^2 = 2rcos(theta) ==> r = 2*cos(theta)

Determine the limits in polar coordinates:

Since the region lies entirely in the first quadrant (x >= 0 and y >= 0), theta ranges from 0 to pi/2.
For a given theta, r ranges from 0 to 2*cos(theta).

3. Transform the Integrand

The integrand is: x / (x^2 + y^2) = (r * cos(theta)) / r^2 = cos(theta) / r

Including the Jacobian r: [ x / (x^2 + y^2) ] dx dy = [ cos(theta) / r ] * r dr dtheta = cos(theta) dr dtheta

4. Evaluate the Integral

I = integral (theta = 0 to pi/2) [ integral (r = 0 to 2*cos(theta)) cos(theta) dr ] dtheta

Inner integral with respect to r: integral (r = 0 to 2cos(theta)) cos(theta) dr = cos(theta) [ r ] from 0 to 2cos(theta) = cos(theta) [ 2cos(theta) - 0 ] = 2 cos^2(theta)

Outer integral with respect to theta: I = integral (theta = 0 to pi/2) 2 * cos^2(theta) dtheta

Using the identity 2cos^2(theta) = 1 + cos(2theta): I = integral (theta = 0 to pi/2) [ 1 + cos(2theta) ] dtheta = [ theta + sin(2theta) / 2 ] from 0 to pi/2 = [ pi/2 + sin(pi) / 2 ] - [ 0 + sin(0) / 2 ] = pi/2 + 0 - 0 = pi/2

Final Answer

The value of the integral is pi / 2.

Q.5 (a)

Question

Define Monotonic sequence. Test the convergence of the sequence {2 - (-1)^n}.

Solution

1. Definition of Monotonic Sequence

A sequence {a_n} of real numbers is said to be monotonic if its terms either consistently increase or consistently decrease for all n in the natural numbers:

Monotonically Increasing: a(n+1) >= an for all n >= 1.
Monotonically Decreasing: a(n+1) <= an for all n >= 1.

If a sequence is either monotonically increasing or monotonically decreasing, it is called monotonic.

2. Test the Convergence of {a_n} = {2 - (-1)^n}

Write out the first few terms of the sequence for n = 1, 2, 3, 4, ...:

For n = 1: a_1 = 2 - (-1)^1 = 2 - (-1) = 3
For n = 2: a_2 = 2 - (-1)^2 = 2 - 1 = 1
For n = 3: a_3 = 2 - (-1)^3 = 2 - (-1) = 3
For n = 4: a_4 = 2 - (-1)^4 = 2 - 1 = 1

The sequence is: {3, 1, 3, 1, 3, 1, ...}

3. Conclusion on Convergence

As n -> infinity, the terms alternate infinitely between 3 and 1:

lim (n -> infinity, n is odd) a_n = 3
lim (n -> infinity, n is even) a_n = 1

Since the sequence oscillates between two distinct values, the limit lim (n -> infinity) a_n does not exist uniquely.

Final Answer

The sequence {2 - (-1)^n} is oscillatory (non-convergent) and does not converge.

Q.5 (b)

Question

Express the function f(x) = log(1 + x) in power series using the formula of Maclaurin’s series.

Solution

1. Maclaurin's Series Formula

The Maclaurin series expansion of a function f(x) about x = 0 is: f(x) = f(0) + f'(0)x + [f''(0)/2!]x^2 + [f'''(0)/3!]x^3 + [f^(4)(0)/4!]x^4 + ... + [f^(n)(0)/n!]*x^n + ...

2. Derivatives and Values at x = 0

Given f(x) = log(1 + x) (natural log):

f(0) = log(1 + 0) = log(1) = 0

First derivative:

f'(x) = 1 / (1 + x) = (1 + x)^(-1)
f'(0) = 1

Second derivative:

f''(x) = -1 * (1 + x)^(-2)
f''(0) = -1

Third derivative:

f'''(x) = 2 * (1 + x)^(-3)
f'''(0) = 2

Fourth derivative:

f^(4)(x) = -6 * (1 + x)^(-4)
f^(4)(0) = -6

Fifth derivative:

f^(5)(x) = 24 * (1 + x)^(-5)
f^(5)(0) = 24

In general, the n-th derivative at x = 0 is: f^(n)(0) = (-1)^(n-1) * (n - 1)!

3. Substitute into the Formula

Substitute the evaluated derivatives into the series: log(1 + x) = 0 + 1x + [(-1)/2!]x^2 + [2/3!]x^3 + [(-6)/4!]x^4 + [24/5!]*x^5 + ...

Simplify the coefficients:

x term: x
x^2 term: -1/2 * x^2
x^3 term: 2/6 x^3 = 1/3 x^3
x^4 term: -6/24 x^4 = -1/4 x^4
x^5 term: 24/120 x^5 = 1/5 x^5

Thus: log(1 + x) = x - x^2/2 + x^3/3 - x^4/4 + x^5/5 - ... for -1 < x <= 1

Final Answer

log(1 + x) = sum_{n=1}^infinity [ ((-1)^(n-1) / n) * x^n ] = x - x^2/2 + x^3/3 - x^4/4 + ...

Q.5 (c)

Question

(i) Test the convergence of sum (n = 1 to infinity) [ n! / (2n + 1)! ]. (ii) State Cauchy’s root test and discuss the convergence of sum (n = 1 to infinity) [ 1 / (log n)^n ].

Solution

Part (i): Convergence of sum_{n=1}^infinity [ n! / (2n + 1)! ]

1. Identify general term: un = n! / (2n + 1)! u(n+1) = (n + 1)! / (2(n + 1) + 1)! = (n + 1)! / (2n + 3)!

2. Apply D'Alembert's Ratio Test: Compute the ratio u(n+1) / un: u(n+1) / un = [ (n + 1)! / (2n + 3)! ] [ (2n + 1)! / n! ] = [ (n + 1) n! / ((2n + 3)(2n + 2)(2n + 1)!) ] * [ (2n + 1)! / n! ] = (n + 1) / [ (2n + 3)(2n + 2) ] = (n + 1) / [ 2(n + 1)(2n + 3) ] = 1 / [ 2(2n + 3) ]

3. Take the limit as n -> infinity: L = lim (n -> infinity) [ u(n+1) / un ] = lim (n -> infinity) [ 1 / (4n + 6) ] = 0

4. Conclusion: Since L = 0 < 1, by D'Alembert's Ratio Test, the series converges.

---

Part (ii): Cauchy's Root Test and sum_{n=2}^infinity [ 1 / (log n)^n ]

1. Statement of Cauchy's Root Test: Let sum un be a positive-term series and let: L = lim (n -> infinity) (un)^(1/n)

If L < 1, the series converges.
If L > 1, the series diverges.
If L = 1, the test is inconclusive.

2. Test the Series: Given u_n = 1 / (log n)^n for n >= 2 (for n=1, log 1 = 0, so the series naturally starts from n = 2):

Compute (un)^(1/n): (un)^(1/n) = [ 1 / (log n)^n ]^(1/n) = 1 / log(n)

3. Take the limit as n -> infinity: L = lim (n -> infinity) (u_n)^(1/n) = lim (n -> infinity) [ 1 / log(n) ] Since log(n) -> infinity as n -> infinity: L = 0

4. Conclusion: Since L = 0 < 1, by Cauchy's Root Test, the series converges.

Q.5 (a) OR

Question

State sandwich theorem for sequence. Show that the sequence u_n = (sin n) / n converges to zero.

Solution

1. Statement of Sandwich (Squeeze) Theorem for Sequences

Let {an}, {bn}, and {cn} be three sequences of real numbers such that: an <= bn <= cn for all n >= N (for some positive integer N).

If: lim (n -> infinity) an = lim (n -> infinity) cn = L

then the sequence {bn} also converges to the same limit: lim (n -> infinity) bn = L

2. Application to u_n = (sin n) / n

For any real number n, the sine function satisfies the inequality: -1 <= sin(n) <= 1

Since n is a positive integer (n >= 1), divide the entire inequality by n: -1/n <= (sin n) / n <= 1/n

Here:

Lower bounding sequence: a_n = -1/n
Middle sequence: u_n = (sin n) / n
Upper bounding sequence: c_n = 1/n

3. Take Limits

Evaluate the limits of the bounding sequences as n -> infinity:

lim (n -> infinity) a_n = lim (n -> infinity) (-1/n) = 0
lim (n -> infinity) c_n = lim (n -> infinity) (1/n) = 0

4. Conclusion

Since -1/n <= (sin n)/n <= 1/n for all n >= 1, and both outer limits equal 0, by the Sandwich Theorem: lim (n -> infinity) [ (sin n) / n ] = 0

Hence, the sequence converges to 0.

Q.5 (b) OR

Question

Using Taylor’s theorem find the approximate value of sqrt(10) up to three decimal places.

Solution

1. Setup Function and Expansion Point

We want to approximate sqrt(10). Let f(x) = sqrt(x) = x^(1/2).

Choose an expansion base point a close to 10 that is a perfect square: Let a = 9, so h = x - a = 10 - 9 = 1.

2. Taylor's Theorem

Taylor's expansion of f(a + h) is given by: f(a + h) = f(a) + h f'(a) + (h^2 / 2!) f''(a) + (h^3 / 3!) * f'''(a) + ...

3. Calculate Derivatives at a = 9

f(x) = x^(1/2)
f(9) = sqrt(9) = 3

f'(x) = (1/2) x^(-1/2) = 1 / (2 sqrt(x))
f'(9) = 1 / (2 * 3) = 1/6

f''(x) = (1/2) (-1/2) x^(-3/2) = -1 / (4 * x^(3/2))
f''(9) = -1 / (4 * 27) = -1 / 108

f'''(x) = (-1/4) (-3/2) x^(-5/2) = 3 / (8 * x^(5/2))
f'''(9) = 3 / (8 243) = 1 / (8 81) = 1 / 648

4. Substitute Values (with h = 1)

sqrt(10) = f(9 + 1) approx f(9) + 1 f'(9) + (1/2) f''(9) + (1/6) f'''(9) = 3 + (1/6) - (1/2) (1/108) + (1/6) * (1/648) = 3 + 1/6 - 1/216 + 1/3888

Convert each fraction to decimal form:

1/6 = 0.166667
1/216 = 0.004630
1/3888 = 0.000257

Calculate step by step: sqrt(10) approx 3 + 0.166667 - 0.004630 + 0.000257 = 3.166667 - 0.004630 + 0.000257 = 3.162037 + 0.000257 = 3.162294

Rounding to three decimal places: sqrt(10) approx 3.162

(Check: 3.162^2 = 9.998244, which is extremely accurate).

Final Answer

The approximate value of sqrt(10) is 3.162.

Q.5 (c) OR

Question

(i) Examine the convergence of the series 1/(12) - 1/(23) + 1/(34) - 1/(45) + ... (ii) State Cauchy’s Integral test for convergence of series and test the convergence of the series sum (n = 1 to infinity) [ n^2 * e^(-n^3) ].

Solution

Part (i): Convergence of 1/(12) - 1/(23) + 1/(3*4) - ...

1. Identify General Term: The given alternating series is: sum{n=1}^infinity (-1)^(n-1) * un where u_n = 1 / [n * (n + 1)].

2. Apply Leibniz's Test for Alternating Series: An alternating series sum (-1)^(n-1) * u_n converges if:

u_n > 0 for all n.
u(n+1) <= un for all n (terms are monotonically decreasing).
lim (n -> infinity) u_n = 0.

Verification of Conditions:

For all n >= 1, u_n = 1 / [n(n + 1)] > 0. (Condition satisfied)
Compare u(n+1) and un:
u_(n+1) = 1 / [(n + 1)(n + 2)]
Since (n + 1)(n + 2) > n(n + 1), it follows that:
1 / [(n + 1)(n + 2)] < 1 / [n(n + 1)] ==> u(n+1) < un.
Thus, {u_n} is strictly decreasing. (Condition satisfied)
Limit:
lim (n -> infinity) u_n = lim (n -> infinity) [ 1 / (n^2 + n) ] = 0. (Condition satisfied)

Conclusion: All three conditions of Leibniz's Test are satisfied. Therefore, the series is convergent (furthermore, it is absolutely convergent by comparison with 1/n^2).

---

Part (ii): Cauchy's Integral Test and sum_{n=1}^infinity [ n^2 * e^(-n^3) ]

1. Statement of Cauchy's Integral Test: Let f(x) be a continuous, positive, and monotonically decreasing function for x >= 1 such that f(n) = un. Then the infinite series sum{n=1}^infinity u_n and the improper integral integral from 1 to infinity of f(x) dx either both converge or both diverge.

2. Test the Series: Given the series: sum_{n=1}^infinity n^2 e^(-n^3) Let f(x) = x^2 e^(-x^3).

Verify Conditions for f(x) on [1, infinity):

Continuous: Product of polynomials and exponentials, hence continuous.
Positive: For x >= 1, x^2 > 0 and e^(-x^3) > 0, so f(x) > 0.
Monotonically decreasing:
f'(x) = 2x e^(-x^3) + x^2 (-3x^2 e^(-x^3)) = x e^(-x^3) * (2 - 3x^3).
For x >= 1, 2 - 3x^3 < 0, so f'(x) < 0. Thus, f(x) is strictly decreasing.

3. Evaluate the Improper Integral: I = integral (x = 1 to infinity) x^2 e^(-x^3) dx = lim (M -> infinity) [ integral (x = 1 to M) x^2 e^(-x^3) dx ]

Use substitution: Let u = -x^3 ==> du = -3x^2 dx ==> x^2 dx = -du / 3

When x = 1: u = -1
When x = M: u = -M^3

I = lim (M -> infinity) [ integral (u = -1 to -M^3) e^u (-du / 3) ] = (1/3) lim (M -> infinity) [ integral (u = -M^3 to -1) e^u du ] = (1/3) lim (M -> infinity) [ e^u ] from -M^3 to -1 = (1/3) lim (M -> infinity) [ e^(-1) - e^(-M^3) ]

As M -> infinity, e^(-M^3) -> 0: I = (1/3) * [ e^(-1) - 0 ] = 1 / (3e)

4. Conclusion: Since the improper integral converges to the finite value 1/(3e), by Cauchy's Integral Test, the series sum_{n=1}^infinity [ n^2 * e^(-n^3) ] is convergent.

Frequently Asked Questions

What is the passing mark for GTU Mathematics - 1 (3110014)?

The theory exam is conducted for 70 marks. The minimum passing threshold is 33% (equivalent to 23 marks out of 70).

How are eigenvalues and eigenvectors calculated for symmetric matrices?

Find the characteristic equation det(A - lambdaI) = 0 and solve for the roots lambda. For each distinct or repeated root, substitute lambda back into (A - lambdaI)X = 0 and use row operations or Gaussian elimination to determine linearly independent eigenvectors.

When is changing the order of integration necessary in double integrals?

Changing the order of integration is necessary when the inner integral cannot be integrated analytically in terms of elementary functions (e.g., sin(y^2)), or when reversing the order makes algebraic computation simpler.

GTU Environmental Sciences (3110007) Semester 1 Summer 2026 Solved Paper

Complete student-friendly worked solutions for GTU Environmental Sciences (3110007) Semester 1 Summer 2026 examination, covering water, air, noise pollution, waste management, green buildings, and smart cities.

Introduction

This document contains detailed, high-scoring, and student-friendly solutions for the Gujarat Technological University (GTU) Bachelor of Engineering Semester 1 examination in Environmental Sciences (Subject Code: 3110007) for Summer 2026. Each solution provides clear headings, comprehensive explanations, real-world examples, and step-by-step methodologies aligned with GTU marking schemes.

Paper Information

University: Gujarat Technological University
Department: Common to All Branches (Engineering)
Semester: 1
Subject: Environmental Sciences
Subject Code: 3110007
Exam: Summer
Year: 2026

Questions and Solutions

Q.1 (a)

Question

List various sources of water pollution in society.

Solution

Sources of Water Pollution in Society

Water pollution occurs when unwanted substances enter water bodies, degrading water quality and making it toxic to humans or aquatic life. The main sources in society include:

Domestic Sewage and Wastewater: Daily household activities like washing, cooking, bathing, and flushing release greywater and blackwater containing pathogens, soaps, and organic wastes directly into drains.
Industrial Effluents: Chemical factories, textile mills, paper industries, and electroplating units discharge untreated toxic effluents containing heavy metals (lead, mercury, cadmium), acids, and dyes into rivers and streams.
Agricultural Runoff: The overuse of synthetic chemical fertilizers, pesticides, insecticides, and weedicides is washed into nearby ponds and rivers during rains or irrigation, leading to nutrient overload.
Solid Waste and Landfill Leachate: Open dumping of municipal solid waste near water bodies leads to toxic liquid runoff (leachate) percolating into groundwater and flowing into surface water.
Religious and Cultural Activities: Immersion of painted idols, scattering of ashes, offerings of flowers, and bathing rituals during festivals contaminate river systems.

Q.1 (b)

Question

Explain the classification of water pollutants with suitable examples.

Solution

Classification of Water Pollutants

Water pollutants are classified into distinct categories based on their physical, chemical, and biological nature:

Pathogenic / Biological Pollutants:

Description: Disease-causing microorganisms introduced mainly through untreated sewage and animal excreta.
Examples: Bacteria (such as Vibrio cholerae, Escherichia coli), viruses (Hepatitis A, Polio), and protozoa (Entamoeba histolytica).

Oxygen-Demanding Wastes (Biodegradable Organic Matter):

Description: Organic materials that consume dissolved oxygen (DO) when decomposed by aerobic microorganisms, leading to fish mortality.
Examples: Domestic sewage, animal manure, plant debris, and food-processing waste.

Inorganic Plant Nutrients:

Description: Water-soluble compounds that act as plant fertilizers, triggering algal blooms and eutrophication.
Examples: Nitrates (NO3⁻) and phosphates (PO4³⁻) derived from chemical fertilizers and synthetic detergents.

Toxic Inorganic Chemicals:

Description: Non-biodegradable chemical substances that persist in water and bioaccumulate in living tissues.
Examples: Heavy metals like mercury, lead, cadmium, arsenic, and mineral acids.

Organic Chemicals:

Description: Synthetic carbon compounds that are toxic to aquatic organisms and often carcinogenic.
Examples: Pesticides (DDT, malathion), industrial solvents (benzene, toluene), polychlorinated biphenyls (PCBs), and petroleum oil slicks.

Sediments and Suspended Solids:

Description: Insoluble soil particles and mineral dust suspended in water, preventing sunlight penetration.
Examples: Silt and clay caused by soil erosion, construction work, and logging.

Thermal and Radioactive Pollutants:

Description: Waste heat from power station cooling towers that reduces dissolved oxygen, and radioactive elements from nuclear operations.
Examples: Hot condenser cooling water, isotopes of uranium and radium.

Q.1 (c)

Question

Explain sources, effects and control measures of water pollution.

Solution

Water Pollution: Sources, Effects, and Control Measures

Water pollution is the contamination of natural water resources (rivers, lakes, groundwater, oceans) due to human actions, rendering the water unfit for drinking, agriculture, or industry.

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1. Sources of Water Pollution

Point Sources: Identifiable, localized discharge points.
Industrial discharge pipes releasing chemicals, acids, and heavy metals.
Municipal sewage treatment outfalls discharging inadequately treated effluent.
Non-Point (Diffuse) Sources: Broad, unconfined land areas from which pollutants wash off during rainfall.
Agricultural surface runoff carrying synthetic fertilizers and pesticides.
Urban stormwater runoff carrying oil, rubber particles, grease, and litter from roads.
Leachate from unlined open garbage dumps seeping into the groundwater table.

---

2. Effects of Water Pollution

Human Health Hazards:
Pathogen-contaminated drinking water causes waterborne diseases like cholera, typhoid, amoebiasis, and jaundice.
Consumption of heavy metals causes chronic poisoning (e.g., Minamata disease from mercury; Itai-Itai disease from cadmium; fluorosis from excess fluoride).
Aquatic Ecosystem Degradation:
Eutrophication: Excess nitrates and phosphates trigger rapid algal blooms. As algae die and decompose, dissolved oxygen (DO) plunges, suffocating fish and other aquatic life.
Thermal Shock: Hot water discharges lower oxygen solubility and alter biological rhythms of fish.
Soil and Food Chain Contamination:
Irrigating crops with toxic wastewater leads to bioaccumulation and biomagnification of persistent toxins through food crops to humans.
Economic Impact: Contaminated water sources drastically raise water purification costs for cities and destroy commercial fishing.

---

3. Control Measures of Water Pollution

Sewage Treatment Plants (STPs): All municipal sewage must undergo primary (physical settling), secondary (biological digestion via activated sludge), and tertiary (disinfection via chlorination or UV) treatment before release.
Effluent Treatment Plants (ETPs): Industries must be mandated to neutralize pH, precipitate heavy metals, and degrade toxic organic chemicals in specialized on-site treatment units.
Sustainable Agricultural Practices: Promote organic farming, bio-fertilizers, and integrated pest management (IPM) to minimize reliance on agrochemicals.
Riparian Buffer Zones: Plant vegetative strips along riverbanks to filter out sediments and nutrients from agricultural runoff before reaching water bodies.
Enforcement of Environmental Laws: Strictly implement regulatory standards (such as the Water Act 1974 in India) with heavy penalties on illegal industrial dumping.

Q.2 (a)

Question

Identify major common air pollutants present in urban areas.

Solution

Major Common Air Pollutants in Urban Areas

Urban atmospheres contain primary pollutants (emitted directly from sources) and secondary pollutants (formed via atmospheric reactions). The major urban air pollutants are:

Particulate Matter (PM10 and PM2.5): Tiny solid particles or liquid droplets from vehicular exhaust, road dust, construction work, and diesel generators.
Carbon Monoxide (CO): A colorless, odorless, toxic gas formed during the incomplete combustion of fossil fuels in motor vehicles and internal combustion engines.
Nitrogen Oxides (NO and NO2, collectively NOx): Formed at high combustion temperatures in automobile engines and thermal power stations.
Sulfur Dioxide (SO2): Released by burning sulfur-bearing fuels like coal and furnace oil in industries and refineries.
Ground-Level Ozone (O3): A secondary pollutant created by the photochemical reaction of NOx and Volatile Organic Compounds (VOCs) in the presence of sunlight.
Volatile Organic Compounds (VOCs): Hydrocarbon vapors released from fuel evaporation, vehicle tailpipes, solvent usage, and paints (e.g., benzene, formaldehyde).

Q.2 (b)

Question

Describe the effects of common air pollutants on environment.

Solution

Effects of Common Air Pollutants on the Environment

Air pollutants cause wide-ranging environmental damage, impacting plants, materials, weather patterns, and ecosystems:

Acid Rain:

Sulfur dioxide (SO2) and nitrogen oxides (NOx) react with atmospheric moisture to form sulfuric acid (H2SO4) and nitric acid (HNO3).
Acid precipitation lowers the pH of lakes and soils, kills aquatic organisms, leaches vital nutrients (like calcium and magnesium) from soils, and corrodes historical monuments (e.g., marble cancer on the Taj Mahal).

Photochemical Smog Formation:

Sunlight induces reactions between volatile organic compounds (VOCs) and nitrogen oxides (NOx) to produce ground-level ozone, peroxyacetyl nitrate (PAN), and hazes.
Smog drastically reduces atmospheric visibility, damages plant foliage, and inhibits photosynthesis.

Damage to Vegetation and Agriculture:

Ground-level ozone enters leaf stomata, burns plant tissue (chlorosis and necrosis), impairs stomatal opening, and causes yield losses in staple food crops like wheat, rice, and soy.
Particulate matter settles on leaf surfaces, physically blocking sunlight and choking stomata.

Climate Change and Global Warming:

Carbon dioxide (CO2), tropospheric ozone, and black carbon (soot) absorb terrestrial infrared radiation, reinforcing the greenhouse effect and shifting global climate patterns.

Material Degradation and Soiling:

Acid gases and particulates accelerate the corrosion of steel structures, discolor painted facades, and erode stone building materials.

Q.2 (c)

Question

Apply suitable measures to control air pollution in an industrial area.

Solution

Control Measures for Air Pollution in an Industrial Area

Controlling industrial air pollution requires a combination of particulate control technologies, gaseous emission scrubbers, process changes, and administrative planning:

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1. Particulate Emission Control Equipment

Cyclone Separators: Centrifugal force is used to separate heavy, coarse dust particles (>10 micrometers) from exhaust gas streams prior to secondary filtration.
Fabric Filters (Baghouses): Industrial flue gases pass through fabric filter bags that capture fine particulate matter (PM2.5 and PM10) with efficiencies exceeding 99%.
Electrostatic Precipitators (ESPs): Flue gas passes through high-voltage discharge wires that impart an electric charge to particles. Charged particles are attracted to oppositely charged grounded plates and periodically knocked off into hoppers.
Wet Scrubbers (Venturi Scrubbers): A liquid spray (usually water) impacts the incoming gas stream to trap dust particles and acidic mists.

---

2. Gaseous Emission Control Technologies

Flue Gas Desulfurization (FGD): Slurries of limestone (calcium carbonate) or lime are sprayed into exhaust ducts to react with SO2, converting it into harmless gypsum (calcium sulfate).
Selective Catalytic Reduction (SCR): Ammonia (NH3) is injected into exhaust gases across a catalyst bed to convert harmful NOx into molecular nitrogen (N2) and water vapor (H2O).
Adsorption via Activated Carbon: Used to capture VOCs and odor-causing organic compounds from solvent use and paint lines.
Thermal Incineration / Afterburners: Volatile hydrocarbons are oxidized to carbon dioxide and water at high temperatures (700°C–800°C).

---

3. Process and Fuel Modifications

Fuel Switching: Replace coal and heavy furnace oil with cleaner burning fuels like natural gas, biomass pellets, or renewable electricity.
Raw Material Substitution: Use low-sulfur coal and solvent-free raw materials.
Good Housekeeping: Regular maintenance of pipelines, seals, and valves to prevent fugitive emissions.

---

4. Urban Planning and Green Belts

Tall Chimneys (Stacks): Build stacks conforming to regulatory height standards to ensure sufficient atmospheric dispersion of residual gases.
Green Belt Development: Plant dense, multi-layered belts of tolerant trees (such as Neem, Peepal, and Ashoka) around the industrial perimeter to absorb gaseous pollutants and capture dust.
Continuous Emission Monitoring Systems (CEMS): Install online real-time sensors to track emission levels and enforce compliance automatically.

Q.2 (c) OR

Question

Explain causes, effects and preventive measures of noise pollution.

Solution

Noise Pollution: Causes, Effects, and Preventive Measures

Noise pollution is defined as unwanted, excessive, or disruptive sound that causes discomfort, annoyance, or physiological harm to humans and animals. It is measured in decibels (dB).

---

1. Causes of Noise Pollution

Transportation Sources: Road vehicles (incessant honking, modified exhausts), railway operations, and aircraft taking off or landing near urban airfields.
Industrial Operations: Heavy machinery like punch presses, grinding mills, metal forges, compressors, diesel generators, and turbines.
Construction and Demolition: Pneumatic drills, jackhammers, earthmovers, cement mixers, and piling machinery.
Domestic and Social Sources: High-decibel public address systems, loudspeakers during festivals, music clubs, generators, fireworks, and domestic appliances like mixers and vacuum cleaners.

---

2. Effects of Noise Pollution

Auditory Health Impacts:
Temporary or Permanent Hearing Loss: Prolonged exposure to levels above 85 dB causes acoustic trauma or Permanent Threshold Shift (PTS).
Tinnitus: Constant ringing or buzzing sensation in the ears caused by cochlear damage.
Non-Auditory Health Impacts:
Cardiovascular Disorders: Chronic noise triggers stress hormones (adrenaline and cortisol), causing elevated blood pressure, hypertension, and higher heart attack risks.
Sleep Disturbance and Fatigue: Lack of deep sleep leads to daytime drowsiness, irritability, and decreased concentration.
Psychological Distress: Heightened anxiety, emotional fatigue, aggression, and reduced mental performance.
Effects on Wildlife: Interferes with animal acoustic communication, echolocation in bats/marine mammals, mating calls, and predator-prey dynamics, driving wildlife out of habitats.

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3. Preventive and Control Measures

Control at Source:
Design quieter machines by using high-grade bearings, vibration dampening pads, and effective intake/exhaust mufflers.
Proper lubrication and routine mechanical maintenance of vehicles and equipment.
Control along Transmission Path:
Install acoustic noise barriers along busy expressways, elevated transit corridors, and plant perimeters.
Plant multi-tiered tree belts (green belts) between highways and residential zones to scatter sound waves.
Use acoustic enclosures and sound-absorbing ceiling/wall materials in factories and auditoriums.
Receiver Protection:
Mandatory use of personal protective equipment (PPE) such as earmuffs and earplugs for industrial workers in high-decibel zones.
Administrative and Legal Regulations:
Demarcate silent zones (100-meter radius around hospitals, schools, and courts) where honking is strictly banned.
Enforce strict decibel limits and night-time curfews on loudspeakers and fireworks.

Q.3 (a)

Question

State the causes of noise pollution.

Solution

Causes of Noise Pollution

Noise pollution stems from both outdoor activities and indoor installations. The main causes include:

Road Traffic and Automobiles: High volume of motorized vehicles, reckless honking, worn-out engines, squealing brakes, and modified silencers.
Industrial Machinery: Continuous running of heavy manufacturing equipment like pneumatic presses, stamping tools, diesel generators, air compressors, and spinning frames.
Construction and Demolition Work: Use of heavy equipment such as jackhammers, stone crushers, excavators, bulldozers, and concrete transit mixers.
Aviation and Railways: Jet aircraft take-offs, landings, low-altitude flights over cities, rail transit horns, and rail-wheel friction on tracks.
Social, Cultural, and Recreational Gatherings: High-power loudspeakers, DJ systems at weddings, religious ceremonies, public processions, and festive firecrackers.

Q.3 (b)

Question

Explain solid waste generation and management methods.

Solution

Solid Waste Generation and Management Methods

Solid waste comprises non-liquid, discarded materials generated by daily human residential, commercial, industrial, and institutional activities.

---

1. Solid Waste Generation

Residential: Food scraps, vegetable peels, packaging paper, plastic bags, discarded glass, textiles.
Commercial & Institutional: Waste paper, cardboard cartons, office supplies, packaging plastics from markets and colleges.
Industrial: Scrap metal, fly ash, slag, processing residues, sludge.
Demolition and Construction: Concrete rubble, bricks, ceramic tiles, scrap timber, drywall.

---

2. Waste Management Methods

Solid Waste Hierarchy
[ Source Reduction / Minimization ] (Most Preferred)
        ↓
[ Segregation & Recycling ]
        ↓
[ Biological / Thermal Processing ] (Composting / Incineration)
        ↓
[ Sanitary Landfilling ] (Least Preferred)

(Schematic, not to scale)

Source Segregation: Separating waste at generation into dry (recyclable), wet (biodegradable organic), and hazardous domestic waste.
Composting (Aerobic and Vermicomposting): Wet organic waste is broken down by microorganisms or earthworms into organic compost/humus, an excellent soil conditioner.
Anaerobic Digestion / Biomethanation: Decomposition of organic waste in an oxygen-free digester producing methane-rich biogas for cooking or power generation.
Incineration (Waste-to-Energy): Controlled combustion of high-calorific, dry, non-recyclable solid waste at high temperatures (850°C–1000°C), converting waste into ash and recovering heat to generate electricity.
Recycling: Material recovery of waste paper, plastics, glass containers, and scrap metals to manufacture new products, conserving raw materials.
Sanitary Landfill: Engineered disposal of unrecyclable, inert residues on lined sites equipped with impermeable geomembranes, leachate collection systems, and landfill gas extraction wells.

Q.3 (c)

Question

Apply proper management practices for biomedical waste in hospitals.

Solution

Biomedical Waste Management Practices in Hospitals

Biomedical waste (BMW) includes all waste generated during medical diagnosis, treatment, surgeries, research, and immunization. Improper handling can cause deadly nosocomial infections, HIV, and Hepatitis.

---

1. Segregation at Source (Color-Coded Segregation)

Proper segregation at the point of origin is the most critical step using standardized color-coded containers:

Yellow Bags (Anatomical & Soiled Waste):
Contents: Human tissues, organs, body parts, placentas, soiled cotton dressings, plaster casts, expired medicines, and cytotoxic drugs.
Treatment: High-temperature Incineration or Plasma Pyrolysis.
Red Bags (Contaminated Recyclable Plastics):
Contents: Disposable tubings, intravenous (IV) bottles and sets, urine bags, syringes without needles, catheters, and rubber gloves.
Treatment: Autoclaving/Microwaving followed by shredding and plastic recycling.
White Translucent Puncture-Proof Containers (Sharps):
Contents: Needles, scalpels, surgical blades, fixed-needle syringes, contamination-prone metal sharps.
Treatment: Autoclaving/dry heat sterilization followed by shredding or encapsulation.
Blue Cardboard Boxes / Puncture-Proof Containers (Glassware & Metal Implants):
Contents: Broken medicine ampoules, glass vials, contaminated microscope slides, and orthopedic implants.
Treatment: Disinfection with sodium hypochlorite followed by autoclaving and glass recycling.

---

2. Handling, Storage, and Transport

Barcoding and Tracking: Implement barcoded waste bags as mandated by BMW Management Rules to log generation time, ward number, and weight.
Dedicated Safe In-House Transport: Dedicated covered trolleys (no open bins) to move waste through designated service corridors.
Interim Storage Limits: Centralized on-site storage area must be secured, well-ventilated, pest-free, and locked; waste must not be held beyond 48 hours.

---

3. Occupational Health and Training

Mandatory Personal Protective Equipment (heavy-duty nitrile gloves, fluid-resistant aprons, safety goggles, face shields, and steel-toe boots) for all sanitation handlers.
Immunization programs against Hepatitis B and Tetanus for all healthcare and housekeeping staff.
Regular training sessions on spill control protocols (e.g., using 1% sodium hypochlorite for blood spills).

Q.3 (a) OR

Question

State the difference between sound and noise.

Solution

Difference Between Sound and Noise

Q.3 (b) OR

Question

Discuss the causes and effects of ozone layer depletion.

Solution

Ozone Layer Depletion: Causes and Effects

The stratospheric ozone layer (located roughly 15 to 35 km above Earth) absorbs harmful ultraviolet (UV-B and UV-C) solar radiation. Its thinning or depletion allows dangerous UV radiation to reach the Earth's surface.

---

1. Causes of Ozone Layer Depletion

Chlorofluorocarbons (CFCs): Previously used as refrigerants, aerosol propellants, and blowing agents in foam manufacturing. In the stratosphere, intense UV light breaks down CFCs, releasing free chlorine radicals.
Chain Reaction: A single chlorine radical can break down over 100,000 ozone molecules:
Cl + O3 → ClO + O2
ClO + O → Cl + O2
Halons: Bromine-containing compounds used in specialty fire extinguishers. Bromine atoms are roughly 40 to 100 times more destructive to ozone than chlorine.
Hydrochlorofluorocarbons (HCFCs): Intermediate substitutes for CFCs that still possess ozone depletion potential.
Carbon Tetrachloride (CCl4) and Methyl Chloroform: Industrial degreasing solvents.
Nitrous Oxide (N2O): Released from agricultural fertilizers; breaks down into nitric oxide (NO) which catalytically destroys ozone.

---

2. Effects of Ozone Layer Depletion

Human Health:
Increased incidence of non-melanoma and melanoma skin cancers.
Accelerated formation of eye cataracts and permanent retinal damage.
Suppression of the human immune system, raising susceptibility to infectious diseases.
Impact on Marine Life:
UV-B penetrates ocean water, killing phytoplankton (the foundation of marine food webs) and destroying fish larvae, crabs, and shrimp populations.
Impact on Terrestrial Plants:
Stunted plant growth, reduced leaf area, inhibited photosynthesis, and reduced crop yields in agricultural plants.
Degradation of Materials:
Accelerates photodegradation and embrittlement of outdoor synthetic polymers, plastics, and surface paints.

Q.3 (c) OR

Question

Explain climate change, acid rain and carbon footprint in detail.

Solution

Climate Change, Acid Rain, and Carbon Footprint

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1. Climate Change

Definition: Long-term, persistent shifts in global temperatures, precipitation patterns, and weather extremes driven primarily by human activities since the industrial revolution.
Underlying Mechanism: Combustion of fossil fuels, deforestation, and industrialization emit vast amounts of greenhouse gases (CO2, CH4, N2O). These gases trap outgoing terrestrial longwave infrared radiation, heating the troposphere.
Key Consequences:
Melting of polar ice sheets and glaciers, leading to accelerated sea-level rise.
Extreme weather events: more frequent and severe droughts, floods, heatwaves, and tropical cyclones.
Ecosystem disruptions, species extinction, coral reef bleaching, and reduced crop productivity.

---

2. Acid Rain

Definition: Precipitation (rain, snow, fog, dew) with a pH lower than natural rainwater (pH < 5.6).
Chemical Mechanism:
Sulfur dioxide (SO2) from coal combustion and nitrogen oxides (NOx) from vehicle engines react with water vapor and oxidants in the atmosphere:
2SO2 + O2 + 2H2O → 2H2SO4 (Sulfuric acid)
4NO2 + O2 + 2H2O → 4HNO3 (Nitric acid)
Impacts:
Soil Chemistry: Leaches vital nutrients (Ca²⁺, Mg²⁺) and mobilizes toxic aluminum ions, damaging forest roots.
Aquatic Ecosystems: Acidifies lakes and streams, causing fish death and loss of aquatic biodiversity.
Built Environment: Dissolves calcium carbonate in marble and limestone structures:
CaCO3 + H2SO4 → CaSO4 + H2O + CO2 (Marble corrosion).

---

3. Carbon Footprint

Definition: The total quantity of greenhouse gas emissions (specifically carbon dioxide and methane equivalents, expressed as CO2e) caused directly and indirectly by an individual, organization, event, or product over a specified period.
Components:
Primary (Direct) Footprint: Emissions under direct control, such as burning petrol in a personal car, natural gas in a stove, or home electricity use.
Secondary (Indirect) Footprint: Embodied emissions from the entire lifecycle of consumer goods purchased (manufacturing, long-distance freight, packaging, and ultimate disposal).
Reduction Strategies: Switching to public transit or electric vehicles, using solar and wind power, eating plant-rich diets, improving home insulation, and adopting circular economy practices.

Q.4 (a)

Question

Define global warming and greenhouse effect.

Solution

Definitions: Greenhouse Effect and Global Warming

1. Greenhouse Effect

Definition: A natural physical phenomenon in which specific trace gases in Earth's atmosphere (greenhouse gases like CO2, H2O vapor, CH4, N2O) absorb outgoing longwave infrared radiation emitted by the Earth's surface and re-radiate it in all directions.
Function: This natural trapping of heat keeps Earth's average surface temperature at an inhabitable +15°C instead of a frigid -18°C.

2. Global Warming

Definition: The progressive, abnormal increase in Earth's average atmospheric and sea surface temperatures over the past century.
Driver: It is driven by the enhanced greenhouse effect, caused by anthropogenic (human) emissions of greenhouse gases from fossil fuel combustion, deforestation, and industrial processes.

Q.4 (b)

Question

Explain the concept of sustainable development.

Solution

Concept of Sustainable Development

1. Definition

As defined by the United Nations Brundtland Commission (1987) in Our Common Future: > "Sustainable development is development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs."

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2. The Three Pillars of Sustainability (Triple Bottom Line)

Sustainable development requires a balance among three interconnected dimensions:

Environmental Sustainability:

Preventing ecological degradation by conserving natural resources.
Minimizing greenhouse gas emissions, protecting biodiversity, and utilizing renewable resources at or below their replenishment rates.

Economic Sustainability:

Fostering stable, equitable economic growth that generates employment and supports clean industry without depleting natural capital.

Social Sustainability:

Ensuring social equity, gender balance, human health, safety, access to education, clean drinking water, and human rights across all communities.

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3. Guiding Principles

Inter-generational Equity: Current generations must leave behind a planet that is healthy and resource-sufficient for future generations.
Intra-generational Equity: Equitable access to resources and wealth across different societies and economic strata today.
Precautionary Principle: Taking preventive action where serious or irreversible environmental harm threatens, even without full scientific certainty.

Q.4 (c)

Question

Apply international mitigation steps for reducing global environmental change.

Solution

International Mitigation Steps for Reducing Global Environmental Change

Addressing global environmental degradation (climate change, ozone loss, biodiversity collapse) requires coordinated international treaties, national policies, and decarbonization strategies:

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1. International Treaties and Frameworks

The Paris Agreement (COP21, 2015):
Legally binding international climate accord committed to limiting global warming to well below 2.0°C, preferably capping it at 1.5°C above pre-industrial baselines.
Signatory countries submit progressively ambitious Nationally Determined Contributions (NDCs) detailing domestic emission-reduction targets every five years.
Montreal Protocol (1987) and Kigali Amendment (2016):
Successfully phased out ozone-depleting substances (CFCs and halons).
The Kigali Amendment mandates the progressive phase-down of Hydrofluorocarbons (HFCs), which are potent greenhouse gases.
UN Sustainable Development Goals (SDGs 2030):
Universal goals such as Goal 7 (Affordable and Clean Energy), Goal 12 (Responsible Consumption and Production), and Goal 13 (Climate Action).

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2. Transition to Clean and Renewable Energy

Phasing out subcritical coal power plants globally and scaling up solar photovoltaic, onshore/offshore wind, green hydrogen, and hydroelectric power generation.
Electrifying transportation networks using Battery Electric Vehicles (EVs) powered by clean power grids.

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3. Economic and Carbon Market Mechanisms

Carbon Pricing and Carbon Taxes: Putting a clear price on carbon emissions to incentivize low-carbon innovation.
Emissions Trading Systems (Cap-and-Trade): Capping total permissible emissions and letting industrial operators trade allowances, rewarding energy-efficient operators.

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4. Carbon Sequestration and Nature-Based Solutions

Afforestation and Reforestation (REDD+ Initiative): Protecting existing tropical rainforests (e.g., Amazon, Congo Basin) to preserve natural carbon sinks.
Carbon Capture, Utilization, and Storage (CCUS): Capturing concentrated CO2 emissions from cement and chemical plants and permanently storing them in deep geological formations.

Q.4 (a) OR

Question

State any three objectives of Green Building.

Solution

Objectives of Green Building

A green building is designed, built, operated, and maintained to minimize negative impacts on the environment while enhancing occupant health and comfort.

Three primary objectives are:

Maximizing Energy Efficiency: Reducing overall operational energy demand through passive architectural design (natural lighting, solar orientation, ventilation) and energy-efficient systems (LED lighting, high-performance HVAC, rooftop solar panels).
Conserving Water Resources: Minimizing freshwater consumption through rainwater harvesting, low-flow plumbing fixtures, greywater recycling, and on-site sewage treatment.
Enhancing Indoor Environmental Quality (IEQ): Providing safe and healthy indoor spaces with adequate natural airflow, day-lighting, thermal comfort, and non-toxic interior materials (low-VOC paints and adhesives).

Q.4 (b) OR

Question

Describe the fundamental principles of Green Buildings.

Solution

Fundamental Principles of Green Buildings

Green buildings follow holistic, sustainable design principles throughout their complete lifecycle—from site selection to eventual demolition:

Sustainable Site Selection and Planning:

Choose sites that avoid sensitive ecosystems, prime agricultural soils, and wetlands.
Prioritize urban infill or brownfield sites with easy access to public transit to curb vehicular emissions.

Energy Efficiency and Renewable Energy Integration:

Passive Design: Orient the building along appropriate sun-path axes to maximize winter daylight while shading summer heat.
Building Envelope Optimization: High-performance double-glazed insulated windows, reflective cool roofs, and exterior wall insulation to lower HVAC cooling loads.
Integration of rooftop solar photovoltaic panels and solar water heaters.

Water Conservation and Management:

Installing low-flow aerated faucets, dual-flush toilets, and waterless urinals.
Integrating rainwater harvesting systems to recharge groundwater aquifers or supply utility tanks.
Treating greywater for reuse in landscape irrigation and toilet flushing.

Eco-Friendly Materials and Resource Conservation:

Prioritizing locally sourced, certified sustainable, and rapidly renewable materials (bamboo, fly-ash bricks, slag-cement).
Incorporating recycled construction aggregates and minimizing construction waste.

Indoor Environmental Quality (IEQ):

Ensuring ample cross-ventilation and daylight to support occupant circadian health.
Using non-toxic building products, including zero- or low-VOC paints, adhesives, sealants, and carpets.

Q.4 (c) OR

Question

Explain benefits and examples of Green Buildings.

Solution

Green Buildings: Benefits and Examples

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1. Benefits of Green Buildings

Environmental Benefits:
Lower Carbon Footprint: Significantly cuts greenhouse gas emissions through reduced energy demand and on-site renewables.
Resource Preservation: Reduces consumption of virgin timber, water, and non-renewable energy.
Waste Diversion: Diverts large volumes of construction and demolition debris away from urban landfills through on-site sorting and recycling.
Economic Benefits:
Substantial Operational Savings: Consistently delivers 30% to 50% lower electricity bills and 40% lower water utility expenses.
Higher Asset Value: Command higher rental yields, lower vacancy rates, and faster property appreciation.
Health and Social Benefits:
Better Occupant Health: Low-VOC materials and high fresh-air exchange rates minimize "Sick Building Syndrome" (eye irritation, headaches, breathing issues).
Increased Productivity: Abundant natural light and better thermal comfort enhance occupant productivity and focus in offices and schools.

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2. Examples of Notable Green Buildings

Suzlon One Earth (Pune, India):
Certified LEED Platinum; one of India's greenest corporate campuses.
100% of its electricity is generated from on-site and off-site renewable sources (solar panels and wind turbines).
Features extensive rainwater harvesting, daylight sensors, and specialized low-energy HVAC systems.
CII-Sohrabji Godrej Green Business Centre (Hyderabad, India):
The first building outside the US to earn LEED Platinum certification.
Features natural wind towers for passive cooling, a vegetated green roof, recycled fly-ash bricks, and an on-site root-zone wastewater treatment system.
The Crystal (London, United Kingdom):
One of the world's most sustainable event buildings, achieving both BREEAM Outstanding and LEED Platinum.
Emits about 70% less CO2 than comparable buildings by using ground-source heat pumps, extensive solar PV arrays, and complete rainwater collection.

Q.5 (a)

Question

List various applications of recycle and reuse in engineering fields.

Solution

Applications of Recycle and Reuse in Engineering Fields

Civil and Construction Engineering:

Using industrial coal fly ash and ground granulated blast-furnace slag (GGBS) as partial replacements for Portland cement in concrete.
Reusing crushed concrete demolition waste as Recycled Concrete Aggregate (RCA) for road sub-bases and pavement construction.
Using shredded post-consumer plastics in modified bitumen mixes for asphalt roads.

Mechanical and Automotive Engineering:

Remanufacturing worn engine blocks, gearboxes, and alternators to original equipment specifications.
Recycling scrap metals (steel, aluminum, copper) via electric arc furnaces to forge vehicle parts with up to 95% less energy than virgin smelting.
Recycling used motor oil through vacuum distillation and hydro-treating into fresh lubricating base oil.

Electrical and Electronics Engineering:

Recovering precious and base metals (gold, silver, copper) from scrap printed circuit boards (PCBs).
Reclaiming lithium, nickel, and cobalt from spent electric vehicle and laptop batteries for manufacturing new battery cells.

Chemical and Environmental Engineering:

Reusing industrial wastewater in cooling towers after tertiary filtration.
Solvent extraction and redistillation to recover expensive industrial solvents in chemical synthesis.

Q.5 (b)

Question

Explain the concept and importance of Smart Cities.

Solution

Concept and Importance of Smart Cities

1. Concept of a Smart City

A Smart City uses digital technologies, Information and Communication Technology (ICT), and the Internet of Things (IoT) to gather real-time data, optimize city operations, manage resources efficiently, and improve the quality of life for its citizens.

Core Structure of a Smart City:
[ IoT Sensors & Field Devices ]
               ↓
[ Fast Communication Network (5G / Fiber) ]
               ↓
[ Central Command & Control Centre (Data Analytics / AI) ]
               ↓
[ Optimized Urban Services: Power, Water, Mobility, Waste ]

(Schematic, not to scale)

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2. Importance of Smart Cities

Resource Optimization: Smart grids, smart water meters, and automated streetlighting match resource distribution to real-time demand, minimizing transmission losses and municipal wastage.
Enhanced Mobility and Reduced Congestion: Intelligent Transportation Systems (ITS) monitor traffic flows, dynamically adjust signal timings, and promote public transit.
Environmental Sustainability: Real-time air quality monitoring networks, automated green-waste management, and energy-efficient infrastructure help cities curb greenhouse emissions.
Public Safety and Security: Integrated city surveillance, automated emergency SOS units, and quick dispatch systems reduce emergency response times.
Economic Growth and Citizen Engagement: Open data platforms and online municipal services make governance transparent, accessible, and attractive to modern enterprises.

Q.5 (c)

Question

Apply smart city concepts for improving urban infrastructure and services.

Solution

Applying Smart City Concepts for Urban Infrastructure and Services

Implementing smart city frameworks involves deploying IoT sensors, artificial intelligence, and unified data networks across key municipal sectors:

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1. Smart Water Infrastructure

Automated Metering Infrastructure (AMI): Ultrasonic smart water meters log real-time consumption data, flag consumer leaks, and discourage water wastage.
Acoustic Leak Detection Sensors: Installed on main water distribution lines to detect underground pipeline bursts or pinhole leaks before major water loss occurs.
Supervisory Control and Data Acquisition (SCADA): Remotely monitors water pressure, chlorine residuals, and flow rates across treatment plants.

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2. Smart Energy and Grid Management

Smart Grids with Advanced Metering: Enable bi-directional energy flows, allowing rooftop solar producers to feed excess energy back to the grid via net metering.
Smart LED Street Lighting: Networked streetlights that automatically dim during low-traffic midnight hours and brighten when motion sensors detect approaching pedestrians or vehicles.

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3. Intelligent Transportation Systems (ITS)

Adaptive Traffic Control Systems (ATCS): Video cameras and induction loops measure queue lengths at junctions, adjusting green-light duration in real time to ease bottlenecks.
Smart Parking Systems: Parking bays fitted with optical or geomagnetic sensors communicate available spots to drivers via mobile apps, cutting down cruising traffic.
Integrated Multi-Modal Transit Ticketing: A single contactless smart card valid across metro lines, city buses, and app-based bike-sharing stands.

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4. Smart Solid Waste Management

Sensor-Equipped Waste Bins: Ultrasonic fill-level sensors detect when bins reach 80% capacity and transmit location alerts to the central dispatch system.
Dynamic Route Optimization for Garbage Trucks: Collection vehicles follow AI-optimized daily routes targeting only full bins, saving fuel and reducing fleet wear.

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5. Integrated Command and Control Centre (ICCC)

A unified central dashboard that pulls data from traffic sensors, utility meters, weather stations, and emergency units, enabling coordinated city management and rapid disaster response.

Q.5 (a) OR

Question

Identify & classify major examples of E-waste.

Solution

Identification and Classification of E-Waste

Electronic waste (E-waste) encompasses discarded electrical or electronic equipment, including all components, subassemblies, and consumables that are part of the product when discarded.

E-waste is broadly classified into the following major categories:

Information Technology and Telecommunication Equipment:

Examples: Personal desktop computers, laptops, monitors (CRT, LCD, LED), computer motherboards, hard disk drives, mobile phones, chargers, servers, network routers, printers, and toner cartridges.

Large Household Appliances (White Goods):

Examples: Refrigerators, deep freezers, washing machines, clothes dryers, dishwashers, air conditioners, and electric water heaters.

Small Consumer Appliances:

Examples: Microwave ovens, vacuum cleaners, electric toasters, electric kettles, hair dryers, and electric shaving kits.

Consumer Electronics and Photovoltaic Panels:

Examples: Television screens, music systems, digital cameras, video recorders, gaming consoles, and end-of-life solar panels.

Electrical and Electronic Tools:

Examples: Portable electric hand drills, electric circular saws, lawn mowers, welding machines, and soldering equipment.

Medical Devices and Monitoring Instruments:

Examples: Discarded ECG monitors, ultrasound scanners, electronic blood pressure meters, dialysis equipment, and smoke detectors.

Q.5 (b) OR

Question

Discuss the principles of 4R’s in environmental protection.

Solution

The Principles of 4R’s in Environmental Protection

The 4R hierarchy represents four prioritized strategies for waste management and resource conservation, ranked from most environmentally desirable to least:

   [ REDUCE ]  (Highest Priority: Stop waste before it starts)
       ↓
   [ REUSE ]   (Use items multiple times in their existing form)
       ↓
  [ RECYCLE ]  (Reprocess waste material into new items)
       ↓
  [ RECOVER ]  (Extract energy or resources from non-recyclables)

(Schematic, not to scale)

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1. Reduce (Source Reduction)

Concept: Lower the absolute volume of resources consumed and minimize waste generated at the source.
Implementation: Eliminating single-use items, purchasing durable goods with minimal packaging, adopting lean manufacturing processes, and digitizing paperwork.
Impact: Cuts consumption of raw materials, avoids manufacturing emissions, and reduces subsequent disposal burdens.

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2. Reuse

Concept: Using a product multiple times for its original purpose or repurposing it without industrial reprocessing.
Implementation: Carrying reusable cloth bags for shopping, using refillable glass bottles, donating old clothing and computers, and maintaining equipment instead of replacing it.
Impact: Extends product lifespans and avoids the energy-intensive processing required for recycling.

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3. Recycle

Concept: Collecting discarded materials, sorting them, and processing them into raw materials to manufacture new products.
Implementation: Melting scrap aluminum cans into new sheets, processing waste paper into cardboard, and pulverizing PET plastic bottles into polyester textile fibers.
Impact: Conserves virgin ores and natural forests, diverts waste from landfills, and reduces primary manufacturing energy.

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4. Recover

Concept: Extracting usable energy or matter from residual waste that cannot be practically recycled.
Implementation: Incinerating high-calorific municipal waste in Waste-to-Energy (WtE) boilers to produce electricity, and recovering biomethane gas from organic matter in anaerobic digesters.
Impact: Generates clean utility power, reduces reliance on coal power, and reduces final landfill volumes by up to 90%.

Q.5 (c) OR

Question

Apply recycle and reuse principles in civil, mechanical and electrical engineering fields.

Solution

Applying Recycle and Reuse Principles Across Engineering Fields

Engineering disciplines play an essential role in circular resource utilization by finding technical applications for waste and byproducts:

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1. Civil Engineering

Recycled Concrete Aggregate (RCA): Crushing concrete from demolished buildings and bridges, sorting it, and using it as aggregate in road bases, pedestrian pavements, and non-structural concrete.
Industrial Byproduct Utilization:
Replacing up to 30–40% of Portland cement with industrial fly ash (from coal power plants) or Ground Granulated Blast Furnace Slag (GGBS) to make denser concrete.
Incorporating foundry sand and steel slag into asphalt mixes for highway construction.
Waste Plastic Roads: Shredded waste plastic bags (PE, PP) are melted and blended with hot aggregate and bitumen (dry process) to construct roads with improved resistance to water penetration and rutting.

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2. Mechanical Engineering

Component Remanufacturing: Reconditioning worn industrial pumps, compressors, alternators, and engine blocks back to original manufacturer specifications, saving 80% of embodied manufacturing energy.
Metal Scrap Recycling: Collecting steel, brass, and aluminum machining turnings and casting scrap, then remelting them in electric induction furnaces to cast new machinery components.
Waste Heat Recovery: Installing heat exchangers and economizers on engine and furnace exhausts to capture hot flue gas and preheat boiler feed water or generate auxiliary power.
Used Lubricating Oil Recycling: De-watering, vacuum-distilling, and hydro-treating dirty crankcase drain oil into high-grade base oils instead of disposing of it.

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3. Electrical Engineering

Urban Mining of E-Waste: Recovering high-value metals (copper wire, silver, gold, and platinum contacts) from decommissioned printed circuit boards and transformers, saving ore mining resources.
Second-Life Battery Energy Storage Systems (BESS): Repurposing electric vehicle (EV) lithium-ion battery packs that drop below 80% automotive capacity into stationary storage units for solar power and backup supplies.
Transformer Refurbishment and Oil Reconditioning: Re-filtering, degasifying, and centrifuging mineral transformer insulating oils to restore breakdown voltage and dielectric strength, doubling the oil's operating life.

Frequently Asked Questions

What are the passing marks for GTU Environmental Sciences (3110007)?

The external end-semester theory exam is conducted for 70 marks. As per GTU examination norms, students must score a minimum of 23 marks (33%) out of 70 to clear the theory component.

How should I structure a 7-mark question in GTU Environmental Sciences to get full marks?

Begin with a concise definition or introduction. Break down the core answer using clear, bold technical headings, numbered lists, and bullet points. Include standard block diagrams or flowcharts where applicable, give real-world industrial or Indian examples, and end with a brief summarizing conclusion.

Which color bag is used for human anatomical waste in biomedical waste management?

Human anatomical waste (such as body parts, tissues, organs, and placentas) must always be segregated in Yellow non-chlorinated plastic bags and disposed of by high-temperature incineration or plasma pyrolysis.

What is the difference between primary and secondary air pollutants?

Primary air pollutants are emitted directly from identifiable sources into the atmosphere (e.g., CO, SO2, NOx, and lead). Secondary air pollutants are not emitted directly; they form in the atmosphere when primary pollutants chemically react with sunlight or moisture (e.g., ground-level ozone, PAN, and acid rain).

C

Java

Mood

Introduction

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Frequently Asked Questions

What is the structure of the GTU Mathematics - 1 (3110014) examination?

Are scientific calculators permitted in the GTU Mathematics - 1 exam?

What are the core topics covered in GTU Mathematics - 1 (3110014)?

Introduction

Paper Information

Questions and Solutions

Q.1 (a)

Problem Statement

Step 1: Identify the Indeterminate Form

Step 2: Combine into a Single Fraction

Step 3: Expand sin(x) using Taylor Series

Step 4: Substitute and Evaluate the Limit

Final Answer

Q.1 (b)

1. Matrix Representation

2. Row Reduction to Echelon Form

3. Consistency Check

Final Answer

Q.1 (c)

1. Definition and Symmetry Analysis

2. Calculate Fourier Coefficient a0

3. Calculate Fourier Coefficient an

4. Write the Complete Fourier Series