1、令x=tan^2tdx=2tantsec^2tdt原式=∫2tantsec^2tdt/tantsec^2t=2∫dt=2t+C=2arctan(√x)+C2、∫dx/(1+cosx)=∫dx/2cos^2(x/2)=∫sec^2(x/2)d(x/2)=tan(x/2)+C3、∫sinxdx/(1+cosx)=∫2sin(x/2)cos(x/2)dx/2cos^2...