∫(x+sinx)dx/(1+cosx)
=∫xdx/(1+cosx)+∫sinxdx/(1+cosx)
=∫xd(x/2)/(cosx/2)^2+∫tan(x/2)dx
=∫xdtan(x/2)+∫tan(x/2)dx
=xtan(x/2)-∫tan(x/2)dx+∫tan(x/2)dx+C
=xtan(x/2)+C