Question

If A is a $3\times 3$ non-singular matrix, then $\det (A^{-1}adjA)$ is equal to

• A. $detA$
• B. $1$
• C. ${(detA)}^2$
• D. ${(detA)}^{-1}$

Answer 1

Answer: (A)

det $(A^{-1}adjA)$ =det $(A^{-1})\det (adjA)$
$={(\det A)}^{-1}{(\det A)}^{3-1}$
$=\det A$