y=xsin2x+cosx的微分

问题描述:

y=xsin2x+cosx的微分

dy=d(xsin2x)+dcosx
=sin2xdx+xdsin2x-sinxdx
=sin2xdx+xcos2xd2x-sinxdx
=sin2xdx+2xcos2xdx-sinxdx
=(sin2x+2xcos2x-sinx)dx