Definition:Normal to Curve

This page is about Normal to Curve. For other uses, see Normal.

Definition

Let $C$ be a curve embedded in the plane.

The normal to $C$ at a point $P$ is defined as the straight line which lies perpendicular to the tangent at $P$ and in the same plane as $P$.

Also see

• Results about normals to curves can be found here.

Sources

• 1933: D.M.Y. Sommerville: Analytical Conics (3rd ed.) ... (previous) ... (next): Chapter $\text {III}$. The Circle: $3$. The normal
• 1992: George F. Simmons: Calculus Gems ... (previous) ... (next): Chapter $\text {B}.23$: Evolutes and Involutes. The Evolute of a Cycloid