Q72 / 180 · KCET 2019 · Mathematics
If \( P \) and \( Q \) are symmetric matrices of the same order then \( P Q-Q P \) is
- Asymmetric matrix
- Correct answerBskew symmetric matrix
- Cidentity matrix
- Dzero matrix
Solution
(B)
Given $P=P^{\prime}$ and $Q=Q^{\prime}$
$(P Q-Q P)^{\prime}=(P Q)^{\prime}-(Q P)^{\prime}$
$=\left(Q^{\prime} P^{\prime}-P^{\prime} Q^{\prime}\right)$
$=Q P-P Q$
$=-[P Q-Q P]$
$\therefore(P Q-Q P)$ is skew symmetric.
Hence, the correct answer is option: 'B'.