Stage 36 · Limits, Derivatives & Their Applications

36.3.1 The Definition of the Derivative

36.3 What a Derivative Really Is: Concept and Geometry

Point 1 of 5

36.3.1 The Definition of the Derivative

Core idea

Write the whole approaching process as one formula: f′(x₀)=lim[f(x₀+Δx)−f(x₀)]/Δx.

Module goal. Promote the derivative from "a number at one point" to "a brand-new function," and nail down its geometric meaning once and for all: the slope of the tangent.
eastmath.com · 36.3 What a Derivative Really Is: Concept and Geometry · 36.3.1 The Definition of the Derivative