Question 44
Let $O$ be the origin of the coordinate system. The point $A(\frac{5}{2}, -\frac{5\sqrt{3}}{2})$ is rotated around $O$ by $2013\pi$ into the point $B$. The point $B$ is reflected across the bisector of the odd quadrants into the point $C$. Find the size of the angle $\angle AOC$.