JNTU
JNTU B.Tech I Year MATHEMATICS I Previous Question Paper (June - 2022 - R13)
Answer any five questions
All questions carry equal marks
Main
Determine the rank of the matrix:
Answer
To find the rank of matrix A, we reduce it to row-echelon form using elementary row operations:
- Perform R2 → R2 - 3R1 and R3 → R3 - R1:
- Perform R3 → R3 - (1/3)R2:
The number of non-zero rows in the row-echelon form is 2. Therefore, the rank of matrix A is 2.
Investigate the values of λ and μ so that the equations x + y + z = 2, x + 2y + 3z = 5, x + 3y + λz = μ have (i) no solution, (ii) a unique solution and (iii) an infinite number of solutions.
Answer
The system of equations can be represented as an augmented matrix [A|B]:
Applying row operations R2 → R2 - R1 and R3 → R3 - R1:
Applying R3 → R3 - 2R2:
Based on the final row:
- Unique solution: Occurs when the coefficient matrix is non-singular, i.e., λ - 5 ≠ 0. Thus, λ ≠ 5 and μ can be any value.
- No solution: Occurs when the rank of the coefficient matrix is less than the rank of the augmented matrix. This happens when λ - 5 = 0 and μ - 8 ≠ 0. Thus, λ = 5 and μ ≠ 8.
- Infinite solutions: Occurs when the rank of both matrices is equal and less than the number of variables. This happens when λ - 5 = 0 and μ - 8 = 0. Thus, λ = 5 and μ = 8.
Reduce the quadratic form 3x2 + 5y2 + 3z2 - 2yz + 2zx - 2xy to the canonical form and also write the nature of the quadratic matrix.
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State Rolle’s theorem and verify it for f(x) = ex sin x in [0, π].
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If x = r cos θ, y = r sin θ then prove that
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Prove that
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Evaluate
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If a substance cools from 370 K to 330 K in 10 min., when the temperature of the surrounding air is 290 K, find the temperature of the substance after 40 min.
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Solve (D2 - 3D + 2)y = cos 3x.
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Solve (D3 - 1)y = 4 cos 2x + ex.
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Solve by method of variation of parameters (d2y / dx2) + 4y = tan 2x.
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Find L{(sin 3t cos t) / t} and L{t2 cos 2t}.
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Find L-1{s2 / ((s2+4)(s2+9))} using Convolution theorem.
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(i) Find the Laplace Transform of L{t3 / (t+1)} and (ii) Find L{t e-t sin 2t}.
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Solve the differential equation by Laplace transforms method: y'' + y' + y = t3, y(0) = 0, y'(0) = 1.
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