fxcos2xdx fcos2xdx

fxcos2xdx ∫ xcos2x dx=(1/2) ∫ xdsin2x =(1/2)x.sin2x -(1/2) ∫ sin2xdx=(1/2)x.sin2x +(1/4)cos2x + C cos^2 x=(cos2x+1)/2∫ xcos^2 xdx =∫ x(cos2x+1)dx/2+C=(∫xcos2xdx+∫xdx)/2+C=(∫xdsin2x+x^2)/4+C =(xsin2x-∫sin2xdx+x^2)/4+C=(2xsin2x+cos2x+2x^2)/8+C ^∫