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JNTU B.Tech I Year MATHEMATICS - I Previous Question Paper (May - 2018 - R13)

B.Tech | I Year | I-I | R13 | May - 2018

Answer PaperPaper Code: 111ABMaximum Marks: 75Time: 3 hours

Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.

Part A

125 marks
a

If A and B are square symmetric matrices of same order then prove that AB + BA is symmetric.

2 marks

Answer

Given A and B are symmetric, AT = A and BT = B. To prove AB + BA is symmetric, we take its transpose: (AB + BA)T = (AB)T + (BA)T = BTAT + ATBT. Substituting the symmetric properties, we get BA + AB = AB + BA. Since the transpose equals the original matrix, AB + BA is symmetric.

b

If one of Eigen vectors of

[[2,2,0],[2,5,0],[0,0,3]]
is
[[1],[2],[0]]
, then find the corresponding Eigen value.

3 marks

Answer

Let A = [[2, 2, 0], [2, 5, 0], [0, 0, 3]] and X = [[1], [2], [0]]. The eigenvalue λ satisfies AX = λX. Calculating AX: [[2, 2, 0], [2, 5, 0], [0, 0, 3]] * [[1], [2], [0]] = [[2(1)+2(2)+0(0)], [2(1)+5(2)+0(0)], [0(1)+0(2)+3(0)]] = [[6], [12], [0]]. This is equal to 6 * [[1], [2], [0]]. Thus, the eigenvalue λ = 6.

c

Find the value of c in Roll’s theorem for

f(x) = sin(x)
in
(0, π)
.

2 marks

Answer

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d

Find the stationary points of the following functions

x^3 + xy^2 - 3x^2 - 3y^2 + 4
.

3 marks

Answer

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e

Evaluate

∫[0 to ∞] x^4 e^(-x) dx
.

2 marks

Answer

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f

Evaluate

∫∫[0 to 2, 0 to x] y dy dx
.

3 marks

Answer

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g

Solve the differential equation

(D^2 - 4D + 13)y = 0
.

2 marks

Answer

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h

Evaluate

[1 / (D^2 - 1)] (x^2 + x)
.

3 marks

Answer

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i

Find

L[t e^t]
.

2 marks

Answer

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j

Find f(t), if

L[f(t)] = 1 / (s - 1)^2
. Hence find
L^(-1) [1 / (s(s - 1)^2)]
using any theorem of Laplace transforms.

3 marks

Answer

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Part B

210 marks
a

Test for the consistency and hence solve the system: x + y + z = 6, x - y + 2z = 5, 3x + y + z = 8, 2x - 2y + 3z = 7.

5 marks

Answer

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b

If λ₁, λ₂, ..., λₙ are the Eigen values of a non singular matrix A of order ‘n’ then prove that the Eigen values of A^(-1) are 1/λ₁, 1/λ₂, ..., 1/λₙ.

5 marks

Answer

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OR
3

Reduce the quadratic form x^2 + 6y^2 + 3z^2 - 4xy + 2yz - 4xz by orthogonal reduction to the canonical form.

10 marks

Answer

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410 marks
a

Verify Lagranges mean value theorem for f(x) = log(x) in [1, e].

5 marks

Answer

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b

Find the maximum and minimum values of x^3 + y^3 - 3axy.

5 marks

Answer

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OR
5

If x = e^θ cos φ, y = e^θ sin φ, find J and verify that J * J' = 1, where J = ∂(x, y) / ∂(θ, φ).

10 marks

Answer

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610 marks
a

Evaluate ∫[0 to a] x^2 √(a^2 - x^2) dx.

5 marks

Answer

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b

Change the order of integration and evaluate ∫[0 to a] ∫[x to a/x] xy dy dx.

5 marks

Answer

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OR
710 marks
a

Prove that ∫[0 to 1] x^(m-1) (1-x)^(n-1) dx = Γ(m)Γ(n) / Γ(m+n).

5 marks

Answer

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b

Evaluate by changing into polar coordinates: ∫[0 to a] ∫[0 to √(a^2-y^2)] (x^2+y^2) dx dy.

5 marks

Answer

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810 marks
a

Find the orthogonal Trajectory of the family of ax^2 = y^2.

5 marks

Answer

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b

Solve the differential equation (D^2 + 9)y = cos 3x + sin 2x.

5 marks

Answer

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OR
910 marks
a

If a population is increasing exponentially at the rate of 2% per year. What will be the percentage increase over a period of 10 years?

5 marks

Answer

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b

Solve by the method of variation of Parameters (d^2y/dx^2) + y = sec x.

5 marks

Answer

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1010 marks
a

Evaluate ∫[0 to ∞] (sin t / t) dt.

5 marks

Answer

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b

Find the inverse Laplace transform of log((s+1)/(s-1)).

5 marks

Answer

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OR
11

Solve the differential equation (D^2 + 1)y = t^2, using Laplace transform given that y(0) = 4, y'(0) = 2.

10 marks

Answer

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About this paper

This page contains the question paper of MATHEMATICS - I from JNTU for B.Tech CHEM I Year I-I, May - 2018, R13.

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