Question:
Let $A=\left(\begin{array}{ccc}0 & 2 q & r \\ p & q & -r \\ p & -q & r\end{array}\right)$. It AAT $A^{T} I_{3}$, then $|p|$ is :
Correct Option: 1
Solution:
A is orthogonal matrix
$\Rightarrow 0^{2}+\mathrm{p}^{2}+\mathrm{p}^{2}=1 \Rightarrow|\mathrm{p}|=\frac{1}{\sqrt{2}}$