Mathematics

Problem

For any square matrix

A

of order

n

, which one of the following statements is always true? a)

A\,\text{adj}\,A = I_n

\text{adj}\,A = |A|\,A^{-1}

A\,\text{adj}\,A = |A|\,I_n

A\,\text{adj}\,A = |A|\,A