\(G(\beta)\begin{bmatrix}cos\beta&0&sin\beta\\0&1&0\\-sin\beta&0&cos\beta\end{bmatrix}\)
|G(β)| = \(cos^2\beta+sin^2\beta\) = 1
Cofactors of A are:
C11 = cosβ C21 = sinα C31 = sinβ
C12 = 0 C22 = 1 C32 = 0
C13 = sinβ C23 = 0 C33 = cosβ
Hence, [G (β)] –1 = G( – β)