For a square matrix $A$ of order $n$, the product $A\,(\text{adj}\,A)$ equals:
- $\text{adj}(A^2)$
- $I_n$
- $A^2$
- $|A|\,I_n$
Show answer and solution
Correct answer: D. $|A|\,I_n$
A·(adj A) = (adj A)·A = |A| Iₙ — the defining property used to derive A⁻¹ = adj A / |A|.