Epitrochoids and hypotrochoids
A point is attached to a circle of radius , then that circle is rolled around the outside of a fixed circle of radius . The path traced out by the point is called an epitrochoid. The point may be any distance from the center of the exterior circle.
If the circle with the attached point is rolled around the inside of the fixed circle, then the path of the point is called a hypotrochoid.
This applet was developed for use with Interactive Calculus, published by Pearson.