If $A=\begin{bmatrix}3 & 0 & -1\\2 & 3& 0\\0 & 4 & 1\end{bmatrix}$, then |adj(adj A)| is :
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 1
$A=\begin{bmatrix}3 & 0 & -1\\2 & 3& 0\\0 & 4 & 1\end{bmatrix}$
$|A|=3(3-0)-1(8-0)$
$=9-8=1$
$|Adj (A)|=|A|^{n-1}$
$=(1)^2=1$ [n = order of matrix]
$⇒|Adj (Adj(A))|=|Adj (A)|^{n-1}$
$=(1)^2=1$