Question

If A is a square matrix of order 3 such that |A| = 2, then write the value of adj (adj A).

Answer 1

For any square matrix A, we have

\[adj(adj A) = \left| A \right|^{n - 2} A\]

\[ \Rightarrow adj(adj A) = 2A \text{     ....................}\left[ \because \left| A \right| = 2 \text{ and }n = 3 \right] \]