What does $\tan^{-1}{\frac{1}{4}}+\tan^{-1}{\frac{2}{9}}$ reduce to?

Question

$\begin{array}{1 1} sin^{-1}\frac{1}{\sqrt5} \\ sin^{-1}\frac{2}{\sqrt5} \\ cos^{-1}\frac{1}{\sqrt5} \\ tan^{-1}\frac{1}{\sqrt5} \end{array}$