MCQ
If for the matrix $A, A^3 = I,$ than $A^{-1} =$
  • $A^2$
  • B
    $A^3$
  • C
    $A$
  • D
    None of these.

Answer

Correct option: A.
$A^2$
$A^3 = I$
$\Rightarrow A^{-1}A^3 = A^{-1}I$
$\Rightarrow IA^2 = A^{-1}I$
$\Rightarrow A^2 = A^{-1}$

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