What is [ ^ -1 ((3)/(4))+ ^ -1 ((4)/(5))]equal to?

\sin \left[\sin ^{-1}\left(\frac{3}{5}\right)+\sin ^{-1}\left(\frac{4}{5}\right)\right]=\sin \left[\sin ^{-1}\left(\frac{3}{5}\right)+\cos ^{-1}\left(\frac{3}{5}\right)\right]\left[\because \sin ^{-1} x+\cos ^{-1} x=\frac{\pi}{2}\right]=\sin \left[\frac{\pi}{2}\right]=1