What is the angle of rotation for the matrix (22−222222)\begin{pmatrix} \frac{\sqrt{2}}{2} & -\frac{\sqrt{2}}{2} \\ \frac{\sqrt{2}}{2} & \frac{\sqrt{2}}{2} \end{pmatrix}(2222−2222)?
30∘30^\circ30∘
45∘45^\circ45∘
60∘60^\circ60∘
90∘90^\circ90∘