Question

найти интеграл xdx/sgrt1+x^2

Answer 1

$int frac{x, dx}{sqrt{1+x^2}} =[, t=1+x^2; ,; dt=2x, dx, ]= frac{1}{2}cdot int frac{dt}{sqrt{t}} =\\=frac{1}{2}cdot 2sqrt{t}+C=sqrt{1+x^2}+C$