Definition:Bitangent

Definition

Let $\CC$ be a curve in the plane.

A bitangent is a straight line which is tangent to $\CC$ at two distinct points.

Also known as

A bitangent is also known as a double tangent, but that term is also used for a different concept.

Hence on $\mathsf{Pr} \infty \mathsf{fWiki}$ we keep the concepts separate.

Also see

• Results about bitangents can be found here.

Sources

• 1989: Ephraim J. Borowski and Jonathan M. Borwein: Dictionary of Mathematics ... (previous) ... (next): bitangent
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): bitangent
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): double tangent: 1.
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): bitangent
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): double tangent: 1.