Question
Question: If A is square matrix such that A<sup>2</sup> = A, then \|A\| equals-...
If A is square matrix such that A2 = A, then |A| equals-
A
0 or 1
B
–2 or 2
C
–3 or 3
D
None of these
Answer
0 or 1
Explanation
Solution
A2 = A
|A2| = |A|
|A|2 = |A|
|A|2 – |A| = 0
|A| [|A| –1] = 0 ̃ |A| = 0 or |A| = 1