Let A be a square matrix. Then,

(A) $A + A^T$ is a symmetric matrix

(B) $A - A^T$ is a skew-symmetric matrix

(C) $AA^T$ is a skew-symmetric matrix

(D) $A^T A$ is a symmetric matrix

Choose the correct answer from the options given below :

The area of the triangle with vertices $(1,4), (2,7)$ and $(4,13)$ is :

If $\begin{bmatrix} 2x & -7 \\ 5y & 8 \end{bmatrix} = \begin{bmatrix} 6 & -7 \\ -5 & 3x + y \end{bmatrix}$, then value of $5x - 3y$ is :

the least non-negative remainder when $3^{17}$ is divided by 7 is :

If $-\frac{1}{3x - 5} \leq 0$, then :

Evaluate $3^{15} \mod(7)$

If the matrix $\begin{bmatrix} a & -2 & 5b \\ 2 & 0 & -15 \\ 15 & 3c & 0 \end{bmatrix}$ is skew-symmetric, then the value of $a^2 + b^2 + c^2$ is: