In: Computer Science
Computer Graphics:
1. Prove that two successive 2D rotations are additive: R(α1)R(α2) = R(α1+α2), where R(α) denotes a 2x2 rotation matrix of rotation angle α.
(Recall that sin(α1+α2) = sinα1cosα2+ cosα1sinα2, and cos(α1+α2) = cosα1cosα2−sinα1sinα2.)