int dx/(x^(1/2) * (x + 1)) = | x^(1/2) = t, x = t^2, dx = 2t dt | =
= 2 * int t * dt/(t * (t^2 + 1)) = 2 * int dt/(t^2 + 1) = 2 * arctg t + C = | t = x^(1/2) | =
= 2 * arctg x^(1/2) + C