21.1.4 Drawing the Graph of a Direct-Proportion Function
21.1 From Coordinates to Direct Proportion: The Plainest Kind of Change
Point 4 of 5
21.1.4 Drawing the Graph of a Direct-Proportion Function
Core idea
Mark the origin and one other point, lay a ruler across them, and there it is — a direct-proportion graph is a straight line through the origin (0,0).
Module goal. Building on the coordinate plane and the idea of a function, meet the simplest family of functions — direct-proportion functions — and lock in the core picture: a graph that's a straight line through the origin.
eastmath.com · 21.1 From Coordinates to Direct Proportion: The Plainest Kind of Change · 21.1.4 Drawing the Graph of a Direct-Proportion Function