Applied Mathematics KP PMS Paper II 2010

K.P.K, PUBLIC SERVICE COMMISSION, PESHAWAR

COMPETATIVE EXAMINATION FOR PROVINCIAL MANAGEMENT SERVICE, 2010

APPLIED MATHEMATICS, PAPER-II

TIME: 3 hours Max Marks: 100

Note: Attempt only FIVE questions, selecting at least ONE question from each section.

Each part carries 10 marks.

SECTION A

Q.1 Solve any two of the following differential equations.

(i)
x + y – a
x + y – b
dy
dx
=
x + y + a
x + y + b

(ii) x · Sin (yx) dy = {y · Sin (yx) – x} dx

(iii) (1 + y2)dy = (Tan-1y – x)dx

Q.2 (a) Under certain conditions, cane sugar is converted into dextrose at a rate which is proportional to the amount unconverted at any time. If out of 75 grams of sugar at t=0, 8 grams are converted during the first 3 minutes. Find the amount converted in 90 minutes.
(b) Apply the method of variation of parameters to solve

d2y
dx2
+ y = tan x

Q.3 (a) Solve the following partial differential equation.

y2p – xyq = x(z – 2y)      where   
p = ∂z∂x ,     
q = ∂z∂y
(b) The variation of an elastic string is governed by the P.D.E.  
2U∂t2 =
2U∂x2.
The length of the string is π and the ends are fixed. The initial velocity is zero and the initial deflection is U(x, 0) = 2(Sinx + Sin3x). Find the deflection u(x,t) of the vibrating string for t > 0.

SECTION B

Q.4 (a) A covariant tensor has components   xy , 2y – z2 , xz   in rectangular coordinates. Find its covariant components in spherical coordinates.
(b) If (ds)2 = r2(dθ)2 + r2Sin2θ(dφ)2. Find the value of.

Q.5 (a) If Aij are the cofactors of aij in a determinant Δ of order 3, then show that aij Akj = Δδik
(b) Prove any two of the following.

(i) curl(gradφ) = 0
(ii) grad(div f) = curl(curl f) + ∇2f
(iii) div(f × g) = g . curlff . curlg

SECTION C

Q.6 (a) Starting with x0 = 3. Use Newton Raphson method to find a root of
x3 – 3x – 5 = 0 , correct to 3 decimal places.
(b) Find by the method of Regula falsi a root of the equation.

x3 + x2 – 3x – 3 = 0 , lying between 1 and 2.

Q.7 (a) Use the method of iteration to solve the equation x = e-x starting with x = 1.
Perform 4 iterations up to 4 decimal places.
(b) Evaluate

0π3

1 – 13Sin2θ dθ , using Simpsons rule with 6 intervals, correct to 3 decimal places.

Q.8 (a) Solve the following system of equations by Jacobi’s method.

4x + y + 3z = 17
x + 5y + z = 14
2x – y + 8z = 12
(b) Solve the following system of equations by using Gauss-Seidel method.

2x – y + 2z = 3
x + 3y + 3z = -1
x + 2y + 5z = 1
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