# Find all positive integral solutions of the equation $\tan^{-1}x+\cot^{-1}y=\tan^{-1}3$
$\begin{array}{1 1}(a)\;x=1,y=2&(b)\;x=0,y=1\\(c)\;x=2,y=3&(d)\;x=2,y=3\end{array}$