If A is a square matrix of order 3 such that |A| = 2,

Question:

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

Solution:

For any square matrix A, we have

$\operatorname{adj}(\operatorname{adj} A)=|A|^{n-2} A$

$\Rightarrow \operatorname{adj}(\operatorname{adj} A)=2 A \quad[\because|A|=2$ and $n=3]$

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