∫x(sinx)^2dx=(1/2)∫x(1-cos2x)dx=(1/4)x^2-(1/2)∫xcos2xdx=(1/4)x^2-(1/4)∫xdsin2x=(1/4)x^2-(1/4)xsin2x +(1/4)∫sin2x dx=(1/4)x^2-(1/4)xsin2x -(1/8)cos2x + C
