Question

If y = cos (sin x²), then dy/dx at x = √π/2 is ... 

(a) -2 

(b) 2 

(c) -2√π/2 

(d) 0

Answer 1

Answer is (d) 0

y = cos (sin x²) 

dy/dx = – sin (sin x²) [cos (x²)] (2x) 

∴ dy/dx at x = √π/2 = -sin (1) [0] = 0