摘要
高等数学教材中对一元函数(多元函数)表示的曲线(曲面)的切线(切平面)与函数导数(偏导数)之间的关系都有相应的结论.但也有一些例外的情况,例如一些函数除讨论点外处处不连接,从而其图形构不成“曲线”,也就无从按照曲线的切线定义获得切线.本文举出了一些导数存在,但不能得到切线的例子,并提出了比较完善的结论.
In the textbook of higher mathomaties a corresponding conclusion has been reached that what relation there is between the curve (the curved surface) denoted by one -dimensional function (muiltivariate function) and functional derivative (partial derivative). However, there are some exceptional cases. For instance, some functions are so un-successive except for the discussed points as to make the diagram be not able to form wrve, or find tagent by means of the definition of the curved tagent. In this paper, the author gives some examples of derivative available without tagent and in the and arrives at a perfect conclusion.
