## Rotation matrices

Show that a rotation by θ followed by a rotation by φ can be expressed as either
two consecutive rotations, or one rotation of (θ + φ). That is, show that Qθ Qφ = Qθ+φ, where Q is the rotation matrix.

Can any one answer this question I'm a beginner in Linear Algebra

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 Blog Entries: 8 Recognitions: Gold Member Science Advisor Staff Emeritus What is the rotation matrix with angle $\theta$??
 do the matrix multiplication and see what happens

Recognitions:
Gold Member
 Quote by micromass What is the rotation matrix with angle $\theta$??
You will need the trig identities $cos(\theta+ \phi)= cos(\theta)cos(\phi)- sin(\theta)sin(\phi)$ and $sin(\theta+ \phi)= sin(\theta)cos(\phi)+ cos(\theta)sin(\phi)$