HPAS 2019 Mathematics Optional Paper-2: Complete Solutions
Welcome to the comprehensive solution guide for the Himachal Pradesh Administrative Service (HPAS) 2019 Mathematics Optional Paper-2. This resource provides detailed, step-by-step solutions designed specifically for civil service aspirants to master the core mathematical concepts and methodologies required for the exam.
Whether you are revising key theorems, practicing previous year questions, or mastering advanced abstract algebra, real analysis, and differential equations, these carefully structured solutions will help streamline your preparation. Use the index below to jump directly to specific questions and topics.
Table of Contents
- Question 1(a): Convergence of Series
- Question 1(b): Harmonic Function & Analytic f(z)
- Question 1(c): Laplace Transform with Unit Step
- Question 1(d): Newton-Raphson Method
- Question 2(a): Conformal Mapping (Semi-infinite Strip)
- Question 2(b): Contour Integration (Cauchy Integral)
- Question 3(a): Cyclic Groups are Abelian
- Question 3(b): One-to-One Correspondence of Cosets
- Question 3(c): Image of Group Homomorphism
- Question 4(a): Compact Metric Spaces
- Question 4(b): Divergence of Improper Integral
- Question 5(a): Gauss-Seidel Method
- Question 5(b): Interpolation (Best Formula)
- Question 6(a): Inverse Laplace Transform
- Question 6(b): Laplace Transform of Periodic Function
- Question 6(c): Initial Value Problem (Laplace)
- Question 7(a): Power Series Solution of ODE
- Question 7(b): Lagrange’s Linear PDE
- Question 8(a): C Language Concepts
- Question 8(b): Extremal of a Functional
- Question 8(c): Riemann Integrability of Continuous Function
HPAS 2019 Maths Optional Paper-2 Question 1(a)
Discuss the convergence of the series:
1 + \frac{x}{2} + \frac{2!}{3}x^2 + \frac{3!}{4}x^3 + \dotsSolution:
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HPAS 2019 Maths Optional Paper-2 Question 1(b)
Examine if the function u = e^{2xy}\sin(x^2 - y^2) is harmonic. Find the complex function f(z) in terms of z, where f(z) = u+iv.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 1(c)
Obtain the Laplace transform of the function f(t) = e^{-3t}u(t-2).
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 1(d)
Obtain the smallest positive root of the equation x \log_{10}x - 1.2 = 0, correct to 2 decimal places, using the Newton-Raphson method.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 2(a)
Find the transformation which maps the semi-infinite strip of width \pi, bounded by the lines v=0, v=\pi, and u=0, into the upper half of the z-plane.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 2(b)
Evaluate
\int_C \frac{3z^2+z}{z^2-1} dzwhere C is the circle |z-1|=1.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 3(a)
Show that a cyclic group is necessarily abelian. Show by an example that the converse may not be true.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 3(b)
Examine if there exists a one-to-one correspondence between the right and left cosets of H in G, if H is any subgroup of G.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 3(c)
If f:G \to G' is a homomorphism, then prove that Im(f) is a subgroup of G'.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 4(a)
Define a compact metric space. Prove that a closed subset of a compact space is compact.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 4(b)
Show that the integral
\int_{a}^{\infty} \frac{x}{1+x^4\sin^2x} dxis divergent.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 5(a)
Solve the following system of equations by the Gauss-Seidel method, correct to 2 decimal places:
\begin{cases} x_1 + 6x_2 + 2x_3 = 6 \\ 5x_1 + x_2 - x_3 = 12 \\ 3x_1 - 2x_2 + 8x_3 = -4 \end{cases}Solution:
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HPAS 2019 Maths Optional Paper-2 Question 5(b)
From the following table, obtain f(2.07) using the best formula:
x: 2.00, 2.05, 2.10, 2.15, 2.20, 2.25
f(x): 0.69315, 0.71784, 0.74194, 0.76547, 0.78846, 0.81093
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 6(a)
Obtain the inverse Laplace Transform of f(s) = \log\frac{s+1}{s-1}.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 6(b)
Find the Laplace transform of the following periodic function f(t) with period 2c:
f(t) = \begin{cases} t & , \ 0 < t < c \\ 2c - t & , \ c < t < 2c \end{cases}Solution:
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HPAS 2019 Maths Optional Paper-2 Question 6(c)
Solve the following Initial Value Problem using the Laplace transform:
x'' + 2x' + 5x = e^{-t}\sin twith initial conditions x(0)=0 and x'(0)=1.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 7(a)
Find the series solution of the following differential equation:
(1+x^2)\frac{d^2y}{dx^2} + x\frac{dy}{dx} - y = 0Solution:
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HPAS 2019 Maths Optional Paper-2 Question 7(b)
Solve the partial differential equation
(x^2 - y^2 - z^2)p + 2xyq = 2xzwhere p = \frac{\partial z}{\partial x} and q = \frac{\partial z}{\partial y}.
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 8(a)
What do the following explain in the C Language:
(i) ++nc
(ii) else if (condition)
(iii) tolower(c)
(iv) Pointer
Solution:
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HPAS 2019 Maths Optional Paper-2 Question 8(b)
Using the Euler equation, find the extremal of the following functional:
\int_{a}^{b} (12xy(x) + (y')^2) dxSolution:
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HPAS 2019 Maths Optional Paper-2 Question 8(c)
Let f be a continuous function. Then show that f is Riemann integrable.
Solution:
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