1
WB JEE 2024
+2
-0.5

Let $$A=\left(\begin{array}{ccc}1 & -1 & 0 \\ 0 & 1 & -1 \\ 1 & 1 & 1\end{array}\right), B=\left(\begin{array}{l}2 \\ 1 \\ 7\end{array}\right)$$

Then for the validity of the result $$\mathrm{AX}=\mathrm{B}, \mathrm{X}$$ is

A
$$\left(\begin{array}{c}-1 \\ 1 \\ 7\end{array}\right)$$
B
$$\left(\begin{array}{l}1 \\ 2 \\ 4\end{array}\right)$$
C
$$\left(\begin{array}{c}3 \\ 1 \\ -1\end{array}\right)$$
D
$$\left(\begin{array}{l}4 \\ 2 \\ 1\end{array}\right)$$
2
WB JEE 2024
+2
-0.5

Let $$A=\left[\begin{array}{ccc}0 & 0 & -1 \\ 0 & -1 & 0 \\ -1 & 0 & 0\end{array}\right]$$, then

A
$$\mathrm{A}$$ is a null matrix
B
$$\mathrm{A}$$ is skew symmetric matrix
C
$$\mathrm{A}^{-1}$$ does not exist
D
$$\mathrm{A}^2=\mathrm{I}$$
3
WB JEE 2023
+1
-0.25

Let A and B are orthogonal matrices and det A + det B = 0. Then

A
A + B is singular
B
A + B is non-singular
C
A + B is orthogonal
D
A + B is skew symmetric
4
WB JEE 2023
+1
-0.25

Let $$A = \left( {\matrix{ 2 & 0 & 3 \cr 4 & 7 & {11} \cr 5 & 4 & 8 \cr } } \right)$$. Then

A
det A is divisible by 11
B
det A is not divisible by 11
C
det A = 0
D
A is orthogonal matrix
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