Question

If A is an invertible matrix, then det (A⁻¹) is equal to
(a) $\det \left(A\right)$
(b) $\frac{1}{det\left(A\right)}$
(c) 1
(d) none of these

Answer 1

(b) $\frac{1}{det\left(A\right)}$

We know that for any invertible matrix A, $\left|A^{-1}\right|$ = $\frac{1}{\left|A\right|}$.