Stage 36 · Limits, Derivatives & Their Applications
36.3.2 The Slope of the Tangent Line
36.3 What a Derivative Really Is: Concept and Geometry
Point 2 of 5
36.3.2 The Slope of the Tangent Line
Core ideaZoom in on the curve until it looks like a straight line, and the steepness of that little piece is f′(x₀).
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.