Which of the following are correct? (A) For a square matrix A, if $A^3 = I$, then $A^{-1} = A^2$. Choose the correct answer from the options given below: |
(A), (B) and (D) only (A), (B) and (C) only (B) and (D) only (C) and (D) only |
(A), (B) and (D) only |
The correct answer is Option (1) → (A), (B) and (D) only (A) If $A^3=I$, then multiplying both sides by $A^{-1}$ gives $A^2=A^{-1}$. Correct. (B) Determinant is defined only for square matrices. Correct. (C) For a $3\times 3$ matrix, the total number of minors = $9$ (one for each element). Hence 3 is wrong. (D) $(AB)^{-1}=B^{-1}A^{-1}$. Correct. |