# Integrate $\ln(x^2+1)/(x^2+1)$ [duplicate]

How to evaluate $$\int_0^\infty \frac{\ln(x^2+1)}{x^2+1} \mathrm{d}x$$ using complex analysis?
This question was merged with Evaluating $\int_0^{\infty}\frac{\ln(x^2+1)}{x^2+1}dx$ because it is an exact duplicate of that question.