If 
then show that 
As A = 
∴ A2 = 
By matrix multiplication:
A2 = 
⇒ A2 = 
As we know that:
2 sin θ cos θ = sin 2θ and cos2 θ – sin2 θ = cos 2θ
∴ A2 = 
…Hence proved
33
If then show that
As A =
∴ A2 =
By matrix multiplication:
A2 =
⇒ A2 =
As we know that:
2 sin θ cos θ = sin 2θ and cos2 θ – sin2 θ = cos 2θ
∴ A2 = …Hence proved