As we saw in Section 9.4, the two-dimensional rotation matrix is R() = cos() sin()

As we saw in Section 9.4, the two-dimensional rotation matrix is R(θ) =



cos(θ) − sin(θ)

sin(θ) cos(θ)



.

What is R

−1

? Check that RR−1 = R

−1R = I. What is the geometrical interpretation of R

−1

, i.e., what does R

−1 do to a vector?