# How to proceed this integral question? [duplicate]

This question already has an answer here:

$$\int_{0}^{1} \frac{\log{(1+x)}}{x^{2}+1} \ dx$$

I tried substituting x with 1/t but couldn't find the answer. Can someone provide any hint?

As many suggested I substituted x with tan t but again I got stuck at $$\int_{0}^{\frac{π}{4}} \log{(1+tant)} \ dt$$

I finally solved it and got the correct answer.

## marked as duplicate by Renascence_5., miracle173, Claude Leibovici, zhoraster, WatsonJan 21 '17 at 10:58

• $x=\tan \theta$ – Anurag A Jan 21 '17 at 7:14

Put $\tan^{-1} x = t$
And $\frac{1}{1 + x^2} dx = dt$
Put $\displaystyle x = \frac{1-t}{1+t}$