Definite Integration Question 10

Question: The value of $ \int_0^{\pi /2}{\log ( \frac{4+3\sin x}{4+3\cos x} )}dx $ is

Options:

A) 2

B) $ \frac{3}{4} $

C) 0

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

Let $ I=\int_0^{\pi /2}{\log ( \frac{4+3\sin x}{4+3\cos x} )}dx. $

Then, $ I=\int_0^{\pi /2}{\log ( \frac{4+3\cos x}{4+3\sin x} )}dx $ , $ [ \because \int_0^{\pi /2}{f(x)dx=\int_0^{\pi /2}{f( \frac{\pi }{2}-x )dx}} ] $

therefore $ I=-\int_0^{\pi /2}{\log ( \frac{4+3\sin x}{4+3\cos x} )dx=-I} $

therefore $ 2I=0\Rightarrow I=0 $ .