Find dydx, if y=sin−1x+sin−1√1−x2,−1≤x,≤1.
Given, y=sin−1x+sin−1√1−x2
Putting sin−1x=θ ⇒ x=sinθ⇒ y=θ+sin−1√1−sin2θ⇒ y=θ+sin−1(cos θ) [∵ 1−sin2θ=cos2θ]⇒ y=θ+sin−1sin(π2−θ)⇒ y=θ+π2−θ=π2(∴ sin(π2−θ)=cos θ)⇒ y=π2
On differentiation w.r.t. x, we get dydx=0