Question:
Find the adjoint of the given matrix and verify in each case that $A .(\operatorname{adj} A)=(\operatorname{adj} A)=m|A| . I$.
$\left[\begin{array}{ccc}\cos \alpha & -\sin \alpha & 0 \\ \sin \alpha & \cos \alpha & 0 \\ 0 & 0 & 1\end{array}\right]$
Solution:
