Let A be any square matrix of order n, then which of the following are true? (A) $|adj\, A| = |A|^{n-1}$ Choose the correct answer from the options given below: |
(A) and (B) only (A), (B) and (D) only (C) and (D) only (B), (C) and (D) only |
(A), (B) and (D) only |
The correct answer is Option (2) → (A), (B) and (D) only (A) $|\text{adj }A| = |A|^{\,n-1}$ This is a standard identity for any square matrix of order $n$. (A) is true. (B) $|A^{-1}| = \frac{1}{|A|}$ Determinant of inverse is reciprocal of determinant. (B) is true. (C) $|\text{adj }A| = |A|^{\,n}$ This is wrong: the correct formula is $|\text{adj }A| = |A|^{\,n-1}$. (C) is false. (D) $(A^{T})^{-1} = (A^{-1})^{\,T}$ Inverse and transpose commute for any invertible matrix. (D) is true. The true statements are (A), (B), and (D). |