$\tan ^{-1}\left(\frac{4}{5}\right)$

$2 \tan ^{-1}\left(\frac{3}{5}\right)$

$\frac{1}{8} \tan ^{-1}\left(\frac{8}{9}\right)$

$\frac{1}{4} \tan ^{-1}\left(\frac{7}{8}\right)$

$\frac{\pi}{6 \sqrt{5}}$

$\frac{\pi}{6}$

$\frac{\pi}{3}$

$\frac{\pi}{3 \sqrt{5}}$

$5+\sqrt{2}+\sqrt{3}$

$5+\sqrt{2}-\sqrt{3}$

$5-\sqrt{2}-\sqrt{3}$

$5-\sqrt{2}+\sqrt{3}$

$e^2-1$

$e^2+1$

$2 e^2-2$

$2 e^2+1$