If $A=\begin{bmatrix}0&x^2-6&-3\\-x&0&-8\\x^2-2x&8&0\end{bmatrix}$ is a skew symmetric matrix, then the value(s) of $x$ is/are- (A) 3 Choose the correct answer from the options given below. |
(A) and (C) only (A), (C) and (D) only (A) only (B), (C) and (D) only |
(A) only |
The correct answer is Option (3) → (A) only ** Matrix $A=\begin{bmatrix}0 & x^{2}-6 & -3\\ -x & 0 & -8\\ x^{2}-2x & 8 & 0\end{bmatrix}$ Skew–symmetry requires $a_{ij}=-a_{ji}$ for all $i\ne j$. From $(1,2)$ and $(2,1)$: $x^{2}-6 = -(-x)\Rightarrow x^{2}-x-6=0$ So $x=3$ or $x=-2$. From $(1,3)$ and $(3,1)$: $x^{2}-2x = -(-3)\Rightarrow x^{2}-2x-3=0$ So $x=3$ or $x=-1$. Common solution: $x=3$. Answer: $x=3$ |