Definite Integration Question 315

Question: The value of $ I=\int_0^{\pi /2}{\frac{{{(\sin x+\cos x)}^{2}}}{\sqrt{1+\sin 2x}}}dx $ is

[AIEEE 2004]

Options:

A) 3

B) 1

C) 2

D) 0

Show Answer

Answer:

Correct Answer: C

Solution:

$ I=\int_0^{\pi /2}{\frac{{{(\sin x+\cos x)}^{2}}}{\sqrt{1+\sin 2x}}dx} $

$ =\int_0^{\pi /2}{\frac{{{(\sin x+\cos x)}^{2}}}{\sqrt{{{(\sin x+\cos x)}^{2}}}}dx} $

$ I=\int_0^{\pi /2}{(\sin x+\cos x)dx=(-\cos x+\sin x)_0^{\pi /2}} $

$ I=1-(-1)=2 $ .