Question

If y = sin^–1 (sin x), then $\frac{dy}{dx}$at x = $\frac{\pi}{2}$is

• A. 1
• B. –1
• C. Non-existent
• D. None of these

Answer 1

Answer: (C)

Non-existent

Answer 2

If y = sin^–1 (sin x) then $\frac{dy}{dx}$at x = $\frac{\pi}{2}$D.N.E.

as $\frac{dy}{dx}$= $\frac{1}{\sqrt{1 - \sin^{2}x}}$× cos x

Ž $\frac{dy}{dx}$

D.N.E. at points when

Dr. = 1 – sin² x = 0

Ž sin x = ±1 & sin x = 1 at x = p/2