一、定义本质1.导数的定义:f′(x_0)=limΔx→0Δy/Δx=limΔx→0f(x0+Δx)-f(x0)/Δx.2.导数的几何意义:f′(x_0)表示曲线y=f(x)在点(x_0,f(x_0))处的切线的斜率.从图形直观我们易得:导数其实上是函数曲线上两点连线斜率的极端情形;曲线的切线可看作是过切点的割线的极限位置;具备凹、凸性的函数曲线必位于其相应切线的上、下方.二、构建模型 I. DEFINITION Essence 1. Definition of derivative: f ’(x_0) = limΔx → 0Δy / Δx = limΔx → 0f (x0 + Δx) -f (x0) /Δx.2. Geometrical meanings of derivatives: f’ (x_0) Represents the slope of the tangent at the point (x_0, f (x_0)) for the curve y = f (x) From the graphical intuition we can easily obtain that the derivative is in fact the extreme case of the slope of the two points on the function curve; the tangent to the curve Can be seen as the cut-off point of the overcut point of the limit position; with concave, convex function curve will be located at the top and bottom of the corresponding tangent. Second, the building model