Identify the correct statements. (A) If A is a non-sigular matrix, then $A^{-1}=\frac{|A|}{(adjA)}$ (B) If A is an invertible matrix then $\frac{1}{|A^{-1}|}=|A|$ (C) If A and B are two invertible matrices of the same order then AB is also invertible matrix and $(BA)^{-1}=A^{-1}B^{-1}$ (D) If A is an invertible matrix, then AT is also invertible and $(A^T)^{-1}=\frac{1}{(A^{-1})^T}$ Choose the correct answer from the options given below : |
(B) and (C) only (B) only (C) and (D) only (A) and (D) only |
(B) and (C) only |
Option B is correct as $|A^n=|A|^n$ n be any integer. $⇒\frac{1}{|A^{-1}|}=|A|$ Option C is also correct as if x, y are two matrices. $xy = yx = 1$, then $x = y^{-1}$ Given $(BA)^{-1}=A^{-1}B^{-1}$ Multiply with BA to $A^{-1}B^{-1}$ $BAA^{-1}B^{-1}=B(AA^{-1})B^{-1}=BB^{-1}=I$ Multiply with $A^{-1}B^{-1}$ with BA $A^{-1}B^{-1}BA=A^{-1}IA=A^{-1}A+I$ $BA(A^{-1}B^{-1})=(A^{-1}B^{-1})BA=I$ $(BA)^{-1}=A^{-1}B^{-1}$ So, statement B and C are correct. |