Q. If $y =$ log (sin($x^{2})),\ 0 < x < \frac{\pi}{2},\ then\frac{dy}{dx}$ at $x = \frac{\sqrt{\pi}}{2}$ is

A) 0
B) 1
C) $\frac{\pi}{4}$
D) $\sqrt{\pi}$
Explanation

(d)
Given, $y = \log{(\sin{(x^{2}))}}$
On differentiating w.r.t. $x,\$we get
$\frac{dy}{dx} = \frac{1}{\sin x^{2}}\ .\cos{x^{2}.2x = 2x\cot x^{2}}$
At $x = \frac{\sqrt{\pi}}{2},\frac{dy}{dx} = \frac{2\sqrt{\pi}}{2}\cot\left( \frac{\sqrt{\pi}}{2} \right)^{2}$
$= \sqrt{\pi}\cot{\left( \frac{\pi}{4} \right) = \sqrt{\pi}}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.