Given T:R2→R2T: \mathbb{R}^2 \to \mathbb{R}^2T:R2→R2 where T(v)=AvT(v) = AvT(v)=Av and A=(0−110)A = \begin{pmatrix} 0 & -1 \\ 1 & 0 \end{pmatrix}A=(01−10), which geometric transformation does this represent?
Reflection across y=xy=xy=x
90 degree counter-clockwise rotation
180 degree rotation
Projection onto the y-axis