微分一般指全微分或者全導(dǎo)數(shù),在這個(gè)方面就沒有區(qū)別,如果是偏導(dǎo)數(shù)就有區(qū)別了.
例如u=x^2y
他的全微分或者全導(dǎo)數(shù)一般寫成：du=2ydx+x^2dy
但對(duì)x的偏導(dǎo)數(shù)=2y,對(duì)y的偏導(dǎo)數(shù)=x^2.???????????????du=2ydx+x^2dy //?????? ????? ????x???????=2y????y???????=x^2.u??x???????=2y??u??y???????=x^2.?????u?????????f(x,y).?????u=f(x,y)=x^2y.