Problems on Circles X: Tangent Circles Generate Ellipses

Initializing live version
Download to Desktop

Requires a Wolfram Notebook System

Interact on desktop, mobile and cloud with the free Wolfram Player or other Wolfram Language products.

The locus of the center (drawn in blue) of a variable circle (in brown) tangent to a fixed (black) circle and passing through a fixed (red) point inside it is an ellipse. This Demonstration lets you change the position of the fixed point or vary the number of tangent circles passing through it. The point is always one of the foci of the ellipse and is the center when the ellipse is a circle. What happens if the point is chosen outside the circle? Just take out the If line to find out!

Contributed by: Jaime Rangel-Mondragon (March 2011)
Open content licensed under CC BY-NC-SA




Feedback (field required)
Email (field required) Name
Occupation Organization
Note: Your message & contact information may be shared with the author of any specific Demonstration for which you give feedback.