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单词 First derivative
释义

First derivative

中文百科

导数 Derivative

(重定向自First derivative)
一个实值函数的图像曲线。函数在一点的导数等于它的图像上这一点处之切线的斜率。
伊萨克·牛顿爵士

导数英语:Derivative)是微积分学中重要的基础概念。一个函数在某一点的导数描述了这个函数在这一点附近的变化率。导数的本质是通过极限的概念对函数进行局部的线性逼近。当函数f的自变量在一点x_0上产生一个增量h时,函数输出值的增量与自变量增量h的比值在h趋于0时的极限如果存在,即为fx_0处的导数,记作f'(x_0)\frac{\mathrm{d}f}{\mathrm{d}x}(x_0)\left.\frac{\mathrm{d}f}{\mathrm{d}x}\right|_{x=x_0}。例如在运动学中,物体的位移对于时间的导数就是物体的瞬时速度。

导数是函数的局部性质。不是所有的函数都有导数,一个函数也不一定在所有的点上都有导数。若某函数在某一点导数存在,则称其在这一点可导,否则称为不可导。如果函数的自变量和取值都是实数的话,那幺函数在某一点的导数就是该函数所代表的曲线在这一点上的切线斜率。

英语百科

Derivative 导数

(重定向自First derivative)
The graph of a function, drawn in black, and a tangent line to that function, drawn in red.  The slope of the tangent line is equal to the derivative of the function at the marked point.
Rate of change as a limit valueFigure 1. The tangent line at (x, f(x))Figure 2. The secant to curve y= f(x) determined by points (x, f(x)) and (x+h, f(x+h))Figure 3. The tangent line as limit of secantsFigure 4. Animated illustration: the tangent line (derivative) as the limit of secants

The derivative of a function of a real variable measures the sensitivity to change of a quantity (a function value or dependent variable) which is determined by another quantity (the independent variable). Derivatives are a fundamental tool of calculus. For example, the derivative of the position of a moving object with respect to time is the object's velocity: this measures how quickly the position of the object changes when time is advanced.

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更新时间:2025/6/20 22:35:16