1
COMEDK 2026 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Given $P=\left[\begin{array}{lll}2 & \boldsymbol{\alpha} & 1 \\ 1 & 2 & 2 \\ 1 & 3 & 3\end{array}\right]$ is the adjoint of a $3 \times 3$ matrix A and $|A|=3$, then the value of $\boldsymbol{\alpha}$ is:

A

7

B

-25

C

-8

D

-26

2
COMEDK 2026 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Given the matrices $A=\left[\begin{array}{lll}1 & 0 & 1 \\ 0 & 1 & 0 \\ 1 & 0 & 2\end{array}\right]$ and $B=\left[\begin{array}{lll}2 & 1 & 0 \\ 1 & 1 & 2 \\ 0 & 2 & 1\end{array}\right]$, then the minor $\boldsymbol{M}_{\mathbf{2 3}}$ of the matrix $\left(A B^{-1}\right)^{-1}$ is:

A

2

B

9

C

4

D

-9

3
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Kiran purchased 3 pencils, 2 notebooks and one pen for ₹41. From the same shop Manasa purchased 2 pencils, one notebook and 2 pens for ₹ 29 , while Shreya purchased 3 pencils, 2 notebooks and 2 pens for ₹ 44. The above situation can be represented in matrix form as $A X=B$. Then $|\operatorname{adj} A|$ is equal to

A
9
B
$-$9
C
$-$1
D
1
4
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0
If $X=\left[\begin{array}{ll}1 & 0 \\ 0 & 1\end{array}\right]$ and $Y=\left[\begin{array}{cc}0 & 1 \\ -1 & 0\end{array}\right]$ and $B=\left[\begin{array}{cc}\cos \theta & \sin \theta \\ -\sin \theta & \cos \theta\end{array}\right]$ then $B$ equals :
A
$-X \cos \theta+Y \sin \theta$
B
$X \sin \theta+y \cos \theta$
C
$X \cos \theta-Y \sin \theta$
D
$X \cos \theta+Y \sin \theta$

COMEDK Subjects

Browse all chapters by subject