$ an ^{-1}\left(\frac{1}{4} ight)+ an ^{-1}\left(\frac{2}{9} ight)=$

Question

$	an ^{-1}\left(\frac{1}{4}ight)+	an ^{-1}\left(\frac{2}{9}ight)=$

Professor PC Thomas Classes · Answer

Addition formula gives $	an^{-1}(1/2) = \cos^{-1}(2/\sqrt{5})$.