Let and . Show that

[G(β)] ^{– 1} = G( – β)

|G(β)| = = 1

Cofactors of A are:

C₁₁ = cos β C₂₁ = sin α C₃₁ = sin β

C₁₂ = 0 C₂₂ = 1 C₃₂ = 0

C₁₃ = sin β C₂₃ = 0 C₃₃ = cos β

Adj G(β) =

=

So, adj G(β) = …… (i)

Now, [G(β)] ^{– 1} =

And, G( – β) =

=

Hence, [G (β)] ^{– 1} = G( – β)