Definite Integration Question 371

Question: $ \int_0^{2\pi }{\sqrt{1+\sin \frac{x}{2}}dx=} $

[MNR 1987; UPSEAT 2000]

Options:

A) 0

B) 2

C) 8

D) 4

Show Answer

Answer:

Correct Answer: C

Solution:

$ \int_0^{2\pi }{\sqrt{1+\sin \frac{x}{2}}dx}=\int_0^{2\pi }{| \sin \frac{x}{4}+\cos \frac{x}{4} |dx=4[ \sin \frac{x}{4}-\cos \frac{x}{4} ]}_0^{2\pi } $

$ =4[1-0-0+1]=8 $ .