多元函数可微性的判定

The decision of the differenability of a function of many varibles

多元函数的可微性一般情况下是通过讨论偏导数的连续性来进行判断的，本文改进了这种方法，将多元函数连续性的讨论弱化为一元函数连续性的讨论，从而使得多元函数可微性的判定变的较为简便。

The differenability of a function of many varibles is usually decided by discussing the continunity of its partial derivative.Here,an improved method is introduced,which transforms the discussing of the continuity of a function of many varibles into the discussing of the countinuity of a function of one varible,and thus simplifies the decision of the differenability of a function of many varibles .