If $A = \begin{bmatrix} -2 & 1 \\ 3 & 4 \end{bmatrix}$ and $A = P + Q$,where $P$ is a symmetric matrix and $Q$ is a skew-symmetric matrix,then $Q$ is:

If $A = \begin{bmatrix} 1 & 2 & 2 \\ 2 & 1 & -2 \\ a & 2 & b \end{bmatrix}$ is a matrix satisfying the equation $A A^T = 9 I$,where $I$ is the identity matrix,then $a^2 + b^2 =$

If $A^2 = A$ is a square matrix such that $(I - A)^n = I - A$ for $n \geq 1$,then what is the value of $(I + A)^2 - 3A$?

Choose the correct option for the matrices given below:
$\begin{aligned} & A=\left[\begin{array}{ccc}\cos \frac{\pi}{4} & \sin \frac{\pi}{4} & 0 \\ -\sin \frac{\pi}{4} & \cos \frac{\pi}{4} & 0 \\ 0 & 0 & 1\end{array}\right] \\ & B=\left[\begin{array}{ccc}1 & 0 & 0 \\ 0 & \cos \frac{\pi}{3} & \sin \frac{\pi}{3} \\ 0 & -\sin \frac{\pi}{3} & \cos \frac{\pi}{3}\end{array}\right] \\ & C=\left[\begin{array}{ccc}\cos \frac{\pi}{6} & 0 & \sin \frac{\pi}{6} \\ 0 & 1 & 0 \\ -\sin \frac{\pi}{6} & \cos \frac{\pi}{6} & 0\end{array}\right] \\ & D=\left[\begin{array}{ccc}\cos \frac{\pi}{2} & \sin \frac{\pi}{2} & 0 \\ -\sin \frac{\pi}{2} & \cos \frac{\pi}{2} & 0 \\ 0 & 0 & 1\end{array}\right]\end{aligned}$

If $A$ is a matrix of order $m \times n$ and $B$ is a matrix such that $AB^{\prime}$ and $B^{\prime}A$ are both defined,then the order of the matrix $B$ is

$A = [a_{ij}]_{m \times n}$ is a square matrix,if