If sin^-1x + sin^-1y=(2π)/3, then cos^-1x + cos^-1y =

We have,

$sin^{-1}x + sin^{-1}y=\frac{2\pi}{3} $

$⇒ \frac{\pi}{2}-cos^{-1}x +\frac{\pi}{2}- cos^{-1}y = \frac{2\pi}{3}$

$ ⇒ cos^{-1}x + cos^{-1} y = \pi -\frac{2\pi}{3}=\frac{\pi}{3}$