Mathematics-1 (Calculus & Linear Algebra) - B.Tech 1st Semester Exam-2022

2022Semester 3Civil-CAEnd Semester
Bihar Engineering University, Patna
B.Tech 1st Semester Exam-2022

Mathematics-1 (Calculus & Linear Algebra)

Time: 03 HoursCode: 105102Full Marks: 70

Instructions:

  1. The marks are indicated in the right-hand margin.
  2. There are NINE questions in this paper.
  3. Attempt FIVE questions in all.
  4. Question No. 1 is compulsory.
Q.1 Choose the correct answer of the following (any seven Question only):[2×7=14]
  1. Lagrange's mean value theorem can be proved for a function f(x) by applying Roll's mean value theorem

    1. \( \varphi(x) = f(x) + kx^2 \)
    2. \( \varphi(x) = f(x) - kx^2 \)
    3. \( \varphi(x) = f(x) + kx \)
    4. \( \varphi(x) = \{f(x)\}^2 + kx^2 \)
  2. The function \( f(x) = x(x + 3) e^{-\frac{x}{2}} \) satisfy all conditions of Roll's mean value theorem in the interval [-3, 0]. Then the value of c is:

    1. 0
    2. 1
    3. 2
    4. -2
  3. if \( \begin{bmatrix} 4/3 \\ 1 \end{bmatrix} \) is an eigenvector of \( \begin{bmatrix} 3 & 4 \\ 3 & 1 \end{bmatrix} \). What is the associated eigenvalue?

    1. 4/3
    2. 5
    3. -2
    4. None of the above
  4. if f is continuous on [-2.354, 2.354] then

    1. \( \int_{-2.354}^{2.354} f(\cos x) dx = 0 \)
    2. \( \int_{-2.354}^{2.354} f(\cos x) dx = 2 \int_{0}^{2.354} f(\cos x) dx \)
    3. 2.354
    4. none of the above
  5. let \( f(x) = |x|^{\frac{3}{2}}, x \in R \) then

    1. f is uniformly continuous
    2. f is continuous, but not differentiable at \( x = 0 \)
    3. f is differentiable, and derivative of f is continuous
    4. f is differentiable, but derivative of \( x \) is discontinuous at \( x = 0 \)
  6. if \( A(2) = 2i - j + 2k, A(3) = 4i - 2j + 3k \), then \( \int_{2}^{3} A \cdot \frac{dA}{dt} dt \) is

    1. 5
    2. 10
    3. 15
    4. 20
  7. if \( \nabla \times \vec{F} \). Then it is called.

    1. solenoidal
    2. Rotational
    3. irrotational
    4. None
  8. if \( 3x + 2y + z = 0, x + 4y + z = 0, 2x + y + 4z = 0 \) be a system of equations, then

    1. It is inconsistent
    2. It has only the trivial solution \( x = 0 \), \( y = 0 \), \( z = 0 \)
    3. Determinant of the matrix of coefficients is zero
    4. None of these
  9. If f(x) is continuous in the closed interval [a,b] and f(x) exists in (a,b) and f(a) = f(b), then there exist at least one value \( c(a < c < b) \) Such that \( f'(c)=0 \) is called

    1. Taylor's theorem
    2. Mac Laurin's theorem
    3. Rolle's theorem
    4. Lagrange's mean value theorem
  10. The rank of the matrix \( \begin{bmatrix} 1 & 2 & 3 \\ 2 & 4 & 6 \\ 3 & 6 & 9 \end{bmatrix} \) is

    1. 3
    2. 2
    3. 1
    4. none of these
Q.2 Solve both questions :[14]
  1. show that : \( \int_{0}^{\infty} x^2 e^{-x^4} dx \times \int_{\infty}^{\infty} e^{-x^4} dx = \frac{\pi}{8\sqrt{2}} \)

  2. Use L' Hospital rule to find the following limits. \( \lim_{x \to 0} \frac{\cos - \ln (1+x) - 1 + xy^x}{\sin^2 x} \)

Q.3 Solve both questions :[14]
  1. Test the convergence of \( 1 + \frac{3}{7} x + \frac{3.6}{7.10} x^2 + \frac{3.6.9}{7.10.13} x^3 + \frac{3.6.9.12}{7.10.13.16} x^4 + \ldots \)

  2. Examine the convergence of the series of which the general term is \( 2^2 4^2 6^2 \cdots \frac{(2n-2)^2}{3.4.5 \cdots (2n-1)2n} x^{2n} \)

Q.4 Solve both questions :[14]
  1. Obtain the fourth-degree Taylor's polynomial approximation to \( f(x) = e^{2x} \) about \( x = 0 \). Find the maximum error when \( 0 \leq x \leq 0.5 \)

  2. It is given the Rolle's theorem holds the function \( f(x) = x^3 + bx^2 + cx, 1 \leq x \leq 2 \) at the Point \( x = 4/3 \). Find the value of b and c.

Q.5 Solve both questions :[14]
  1. Evaluate \( \int_{0}^{\infty} \log \left( x + \frac{1}{x} \right) \frac{dx}{1+x^2} \)

  2. Discuss the convergence of the sequence whose n-th term is \( a_n = \frac{(-1)^n}{n} + 1 \).

Q.6 Solve both questions :[14]
  1. if \( f(x) = \log (1 + x), x > 0 \) using Maclaurin's theorem, show that for \( 0 < \theta < 1 \), \( \log (1 + x)=x - \frac{x^2}{2} + \frac{x^3}{3(1+\theta x)^3} \). Deduce that \( \log (1+x)=< x - \frac{x^2}{2} + \frac{x^3}{3} \) for \( x> 0 \)

  2. Using Taylor's theorem, express the polynomial \( 2x^3 + 7x^2 + x - 6 \) in powers of (x - 1).

Q.7 Solve both questions :[14]
  1. Find the values of a,b,c if A = \( \begin{bmatrix} 0 & 2b & c \\ a & b & -c \\ a & -b & c \end{bmatrix} \) is orthogonal?

  2. Verify Cayley-Hamilton theorem for the matrix A = \( \begin{bmatrix} 1 & 4 \\ 2 & 3 \end{bmatrix} \) and find its inverse. Also express \( A^5 - 4A^4 - 7A^3 + 11A^2 - A - 10I \) as a linear polynomial in A.

Q.8 Solve both questions :[14]
  1. Expand \( \ln x \) in power of \( (x - 1) \) by Taylor's theorem.

  2. By using Beta function evaluate \( \int_{0}^{1} x^5 (1 + x^3)^{10} dx \).

Q.9 Solve both questions :[14]
  1. Find the Fourier series to represent the function defined as \( f(x) = \begin{cases} x + \frac{\pi}{2}, & -\pi < x < 0 \\ \frac{\pi}{2} - x, & 0 < x < \pi \end{cases} \)

  2. Evaluate: (i) div F and Curl F, where F= grad \( (x^3 + y^3 + z^3 - 3xyz) \). (ii) If \( F = (x + y + z) i + j - (x + y)k \) show that \( F \cdot \text{Curl} F = 0 \).