If sin-1x+sin-1y=2π3, then the value of cos-1x+cos-1y is:
(2)
Ans. π3
Explanation:
sin-1x+sin-1y=2π3
⇒ (π2-cos-1x)+(π2-cos-1y)=2π3 [∵ sin-1x+cos-1x=π2]
⇒ cos-1x+cos-1y=π-2π3=π3