Now, |A| = cos (cos ) + sin (sin )

= 1

Hence, A ^{– 1} exists.

Cofactors of A are

C₁₁ =

C₁₂ =

C₂₁ =

C₂₂ =

Since, adj A =

(adj A) =

=

Now, A ^{– 1} = .adj A

A ^{– 1} = .

A ^{– 1} =