1
NDA Mathematics 14th September 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language
For the following two (02) items:
Let
$A=\left[\begin{matrix}\cos \theta &\sin \theta \\ -\sin \theta &\cos \theta \end{matrix}\right] $
What is $[adj A ]^ {-1}$ equal to?
1
-A
2
$ - A ^ T$
3
A
4
$A ^ T$
2
NDA Mathematics 14th September 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language

Consider the following statements:

Statement-l: If X is an nn matrix, then det(mX) = $m ^ n$ det(X), where m is a scalar.

Statement-II: If Y is a matrix obtained from X by multiplying any row or column by a scalar m, then det (Y) = m det (X).

Which one of the following is correct in respect of the above statements?

1
Both Statement-1 and Statement-II are correct and Statement-II explains Statement-I
2
 Both Statement-I and Statement-II are correct but Statement-II does not explain Statement-1
3
Statement-I is correct but Statement-II is not correct
4
 Statement-I is not correct but Statement-II is correct
3
NDA Mathematics 14th September 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language

Consider the following statements about

the matrix $M=\left[\begin{matrix}71&23&48\\ 57&28&29\\ 65&17&48\end{matrix}\right]$ 

Statement-I: The inverse of M does not exist.

Statement-II: M is non-singular.

Which one of the following is correct in respect of the above statements?

1
Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
2
Both Statement-I and Statement-II are correct but Statement-II does not explain Statement-I
3
Statement-I is correct but Statement-II is not correct
4
 Statement-I is not correct but Statement-II is correct
4
NDA Mathematics 13 April 2025
MCQ (Single Correct Answer)
+2.5
-0.833
Change Language

If $\Delta = \begin{vmatrix} a & b & c \\ d & e & f \\ g & h & i \end{vmatrix} $ 

and A, B, C, D, G are the cofactors of the elements a, b, c, d, g respectively, then what is equal to?

A
0
B
1
C
Δ
D
Δ