Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Matrices

Question:

If A and B are invertible matrices of the same order, then which of the following statement is not true ?

Options:

$|A^{-1}|=|A|^{-1}$

$|A|A^{-1}=AdjA$

$(A+B)^{-1}=B^{-1}+A^{-1}$

$(AB)^{-1}=B^{-1}A^{-1}$

Correct Answer:

$(A+B)^{-1}=B^{-1}+A^{-1}$

Explanation:

$\text{Given }A,B \text{ are invertible matrices.}$

$|A^{-1}|=|A|^{-1}\;\text{True}.$

$|A|A^{-1}=\text{Adj }A\;\text{True}.$

$(AB)^{-1}=B^{-1}A^{-1}\;\text{True}.$

$(A+B)^{-1}=A^{-1}+B^{-1}\;\text{Not true in general}.$

$\text{Not true statement is }(A+B)^{-1}=B^{-1}+A^{-1}.$