求下列不定积分1.∫sinx/（1+sinx）dx 2.∫（xcosx）/sin²xdx

∫sinxdx/(1+sinx)=∫dx-∫dx/(1+sinx) 1+sinx=1+cos(π/2-x)=2cos(π/4-x/2)^2=∫dx-∫d(x/2)/cos(π/4-x/2)^2=x+tan(π/4-x/2)+C ∫xcosxdx/(sinx)^2=∫xd(-1/sinx)=x*(-1/sinx)+∫dx/sinx=-x/sinx-(1/2)ln|1+cosx...