A transformation is defined by (x′y′)=(0.6−0.80.80.6)(xy)\begin{pmatrix} x' \\ y' \end{pmatrix} = \begin{pmatrix} 0.6 & -0.8 \\ 0.8 & 0.6 \end{pmatrix} \begin{pmatrix} x \\ y \end{pmatrix}(x′y′)=(0.60.8−0.80.6)(xy). What is the angle of rotation?
30∘30^\circ30∘
45∘45^\circ45∘
53.1∘53.1^\circ53.1∘
60∘60^\circ60∘