Question

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

Answer 1

For any square matrix A, we have

\[\left| adj(adj A) \right| = \left| A \right|^{(n - 1)^2 }\]

\[ \Rightarrow \left| adj(adj A) \right| = \left( 3 \right)^4 = 81\]