摘要:导函数固然也是函数,但并非每个函数都可以是某个函数的导函数,导函数具有一般函数所没有的某些重要特性 。但是,导函数毕竟是由一般函数派生所得,因而具备一些独有的性质及相关结论。本文主要讨论导函数的几个重要特性:导函数的介值性、导函数无第一类间断点、导函数极限定理和导函数的有界性等,并讨论了导函数的相关应用。
关键词:导函数;介值性;间断点;极限;有界性
Abstract:Derivative is also a function, but not every function can be a function of the derivative. Derivative has the general function does not have certain important characteristics. But, after all, derivative is composed of general function derivative income, thus it has some unique properties and related conclusions. This paper mainly discusses several important properties of derivatives: derivatives with intermediate value property, derivatives has no discontinuity points of the first kind, derivatives limit theorem and the derivatives of the boundedness and applications.
Key Word: Derivative; The intermediate value property; Discontinuous point; Limit; Boundedness
导数(Derivative)是微积分中的重要基础概念。当自变量的增量趋于零时,因变量的增量与自变量的增量之商的极限。导数的最初思想是由法国数学家费马(Fermat)为了研究极值问题而引入的,但与导数概念直接相联系的是以下两个问题:已知运动规律求速度,和已知曲线求它的切线。这是由英国数学家牛顿(Newton)和德国数学家莱布尼茨(Leibniz)分别在研究力学和几何学过程中建立起来的。亦名微商,由速度变化问题和曲线的切线问题而抽象出来的数学概念。