Question

Интеграл от arctgx/1+x^2 fx

Answer 1

$intlimits { frac{arctgx }{1+x^2} } , dx ={arctgx=u,,,du= frac{1}{x^2+1}dx}=\= intlimits {u} , du= frac{u^2}{2}+C= frac{arctg^2x}{2} +C$