Question

If |A| = 2, where A is 2 × 2 matrix, find |adj A|.

Answer 1

\[\text{ For any square matrix A of order n, }\left| adjA \right| = \left| A \right|^{n - 1} . \] 
\[\text{ Given: }\hspace{0.167em} \left| A \right| = 2\] 
Here, order is 2 . 
\[ \Rightarrow \left| adjA \right| = \left| 2 \right|^{2 - 1} = 2\]