∫（COS2X）／（1十SinXCOSX）dX
=∫(1/2)/(1+sin2x/2)d(sin2x)
=∫(1/2)/(1+u/2)du(u=sin2x)
=∫1/(u+2)d(u+2)
=ln|u+2|+C
=ln|sin2x+2|+C
=ln(sin2x+2)+C