Inverse OF square matrix || Orthogonal matrix

Square matrix and diagonal matrix

Transpose OF matrix || Orthogonal matrix||Symmetrical and Skew symmetrical||Adjoint OF matrix||Determinent OF matrix

In which of the following type of matrix there always exists an inverse? (a) Idempotent matrix (c) Involutary matrix (b) Orthogonal matrix (d) None of these

A square matrix A is called orthogonal if.

If nth-order square matrix A is a orthogonal, then |"adj (adj A)"| is