求全微分:z=xcos(x-y)

分类: 作业答案 • 2022-04-06 13:05:59

问题描述：

求全微分:z=xcos(x-y)
$(acontent)

答

z=xcos(x-y)
zx=cos(x-y)-xsin(x-y)
zy=xsin(x-y)
所以
dz=zxdx+zydy=[cos(x-y)-xsin(x-y)]dx+xsin(x-y)dy