Q. $\int_{0}^{\pi/2}\frac{\sqrt{\cot x}}{\sqrt{\cot x} + \sqrt{\tan x}}dx$ is equal to

A) 1
B) $- 1$
C) $\frac{\pi}{2}$
D) $\frac{\pi}{4}$
Explanation

(d)
Let $I = \int_{0}^{\pi/2}\frac{\sqrt{\cot x}}{\sqrt{\cot x} + \sqrt{\tan x}}dx$ …(i)
$\Rightarrow \ I = \int_{0}^{\pi/2}{\frac{\sqrt{\tan x}}{\sqrt{\cot x} + \sqrt{\tan x}}dx}$ …(ii)
$\left\lbrack put\ x = \left( \frac{\pi}{2} - x \right) \right\rbrack$
On adding Eqs. (i) and (ii), we get
$2I = \int_{0}^{\pi/2}{1\ dx = \frac{\pi}{2}\ \Rightarrow \ I = \frac{\pi}{4}}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

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

Want more practice?
Practice Integrals MCQs