Definite Integration Question 86

Question: The value of $ \int _{-2}^{2}{[ p\ln ( \frac{1+x}{1-x} )+q\ln {{( \frac{1-x}{1+x} )}^{-2}}+r ]dx} $ depends on

[Orissa JEE 2003]

Options:

A) The value of p

B) The value of q

C) The value of r

D) The value of p and q

Show Answer

Answer:

Correct Answer: C

Solution:

Since $ \log ( \frac{1+x}{1-x} ) $ is an odd function
$ \therefore \int _{-2}^{2}{{ p\log ( \frac{1+x}{1-x} )+q\log {{( \frac{1-x}{1+x} )}^{-2}}+r }dx} $

$ =r\int _{-2}^{2}{dx}=4r. $

Hence depends on the value of r.