alleryFor a square matrix $A$ of order $n$, the product $A\,(\text{adj}\,A)$ equals:
A$\text{adj}(A^2)$
B$I_n$
C$A^2$
D$|A|\,I_n$
Answer & 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|.
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