Definition:Dandelin Spheres/Parabola

Definition

Let $\CC$ be a double napped right circular cone with apex $O$.

Let $\PP$ be a plane which intersects $\CC$ to form a parabola.

Then it is possible to construct one sphere $\SS$ so that it has ring-contact with $\CC$ such that $\PP$ is tangent to $\SS$.

Also see

• Dandelin's Theorem

• Results about Dandelin spheres can be found here.

Source of Name

This entry was named for Germinal Pierre Dandelin.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): Dandelin sphere
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): Dandelin sphere