If A is a square matrix of order n such that |adj (adj A)|=|A|9, then the value of n can be
either 4 or 2
None of these
We know that for a square matrix of order n, |adj A| =|A|n−1
⇒ |adj (adj A)|=|adj A|n−1=|A|(n−1)2=|A|9⇒ (n−1)2=9⇒n2−2n−8=0
⇒ n = 4 as n =-2 is not possible.