Find the value of $\tan^2\alpha+\cot^2\beta$ A circle with centre o have two chords AC and BD,which are intersecting each other at P.If $\angle AOB=15^\circ$ and $\angle APB=30^\circ$,then find out value of 
$$\tan^2\angle APB+\cot^2\angle COD$$
I want to do it as quick as possible this is an objective question so there is no need to  describe steps.

Hint: $\angle COD = 45^\circ$ (or $315^\circ$, depending on how you measure it). As John mentioned, we know $\angle APB = 30^\circ$.
This is the quickest way, and I've not described any steps like you requested.
