Stage 36 · Limits, Derivatives & Their Applications

36.3.5 How Differentiability and Continuity Relate

36.3 What a Derivative Really Is: Concept and Geometry

Point 5 of 5

36.3.5 How Differentiability and Continuity Relate

Core idea

A curve with a sharp corner has no single tangent, so being differentiable always means being continuous, but being continuous doesn't guarantee differentiable.

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 · 36.3.5 How Differentiability and Continuity Relate