∫dx/sin2x+2sinx=∫dx/2sinx(cosx+1)=∫dx/8sin(x/2)cos(x/2){cox(x/2)}^2=1/4∫1/sin(x/2)cos(x/2)dtan(x/2)=1/4∫(cos(x/2)/sin(x/2)+sin(x/2)/cos(x/2)dtan(x/2)=1/4∫1/tan(x/2)dtan(x/2)+1/4∫tan(x/2)dtan(x/2)=1/4ln绝对值tan(x/2)+1/8{tan(x/2)}^2+C