NDA & NA Exam (I)- 2024 - Mathematics Defence Question Paper

NDA Previous Year Question Papers Question Papers
NDA & NA Exam (I)- 2024 - Mathematics

NDA & NA Exam (I)- 2024 - Mathematics Defence Questions

21.
What is the number of different matrices, each having 4 entries that can be formed using 1, 2, 3, 4 (repetition is allowed)?
A.
72
B.
216
C.
254
D.
768
ANSWER :
D. 768
22.
Let \( A = \{x \in \mathbb{R} : -1 < x < 1\} \). Which of the following is/are bijective functions from A to itself?
1. \( f(x) = x|x| \)
2. \( g(x) = \cos(\pi x) \)
Select the correct answer using the code given below.
A.
1 only
B.
2 only
C.
Both 1 and 2
D.
Neither 1 nor 2
ANSWER :
A. 1 only
23.
Let R be a relation on the open interval (−1, 1) and is given by \( R = \{(x, y) : |x + y| < 2\} \). Then which one of the following is correct?
A.
R is reflexive but neither symmetric nor transitive
B.
R is reflexive and symmetric but not transitive
C.
R is reflexive and transitive but not symmetric
D.
R is an equivalence relation
ANSWER :
D. R is an equivalence relation
24.
For any three non-empty sets A, B, C, what is \( (A \cup B) - \{(A - B) \cup (B - A) \cup (A \cap B)\} \) equal to?
A.
Null set
B.
A
C.
B
D.
\( (A \cup B) - (A \cap B) \)
ANSWER :
A. Null set
25.
If a, b, c are the sides of triangle ABC, then what is
\( \begin{vmatrix} a^{2} & b\sin A & c\sin A \\ b\sin A & 1 & \cos A \\ c\sin A & \cos A & 1 \end{vmatrix} \)
equal to?
A.
Zero
B.
Area of triangle
C.
Perimeter of triangle
D.
\( a^{2} + b^{2} + c^{2} \)
ANSWER :
A. Zero
26.
If a, b, c are in AP; b, c, d are in GP; c, d, e are in HP, then which of the following is/are correct?
1. a, c and e are in GP
2. \( \frac{1}{a}, \frac{1}{c}, \frac{1}{e} \) are in GP
Select the correct answer using the code given below.
A.
1 only
B.
2 only
C.
Both 1 and 2
D.
Neither 1 nor 2
ANSWER :
C. Both 1 and 2
27.
What is the number of solutions of \( \log_{4}(x - 1) = \log_{2}(x - 3) \)?
A.
Zero
B.
One
C.
Two
D.
Three
ANSWER :
B. One
28.
For \( x \geq y > 1 \), let \( \log_{x}\left(\frac{x}{y}\right) + \log_{y}\left(\frac{y}{x}\right) = k \), then the value of k can never be equal to
A.
−1
B.
\( -\frac{1}{2} \)
C.
0
D.
1
ANSWER :
D. 1
29.
If \( A = \begin{bmatrix} \sin 2\theta & 2\sin^{2}\theta - 1 & 0 \\ \cos 2\theta & 2\sin\theta\cos\theta & 0 \\ 0 & 0 & 1 \end{bmatrix} \), then which of the following statements is/are correct?
1. \( A^{-1} = adj A \)
2. A is skew-symmetric matrix
3. \( A^{-1} = A^{T} \)
Select the correct answer using the code given below.
A.
1 only
B.
1 and 2
C.
1 and 3
D.
2 and 3
ANSWER :
C. 1 and 3
30.
What is the coefficient of \( x^{10} \) in the expansion of \( (1 - x^{2})^{20}\left(2 - x^{2} - \frac{1}{x^{2}}\right)^{-5} \)?
A.
−1
B.
1
C.
10
D.
Coefficient of \( x^{10} \) does not exist
ANSWER :
A. −1