We Have The Rotation Matrix Begin Pmatrix Cos Theta Sin Theta Sin Theta Cos Th
We have the rotation matrix
begin{pmatrix}
costheta & -sintheta
sintheta & costheta
end{pmatrix}
**Proof**: there isn’t exist a vector $u in {mathbb{R}^2}$ ($uneq0$) such $Au=u$ where $A$ is the rotation matrix.
