№1

∫xsin2xdx = 1/4 (sin(2x) - 2xcos(2x)) + C

№2

∫dx/(x² + 7x + 11) =  ( log(2x + √5 - 7) - log(2x + √5 + 7) ) / √5    + c

№3

∫dx/(2sinx + 3cosx + 3) = 1/2 (-log(cos(x/2)) + log(3 cos(x/2) + 2 sin(x/2))) + C