## hypocycloid

hy·po·cy·cloidGeom. the curve traced by a point on the circumference of an epicycle that rolls around the inside of a fixed circle

Origin of hypocycloid

hypo- + cycloid## hypocycloid

noun

The plane locus of a point fixed on a circle that rolls on the inside circumference of a fixed circle.

**hypocycloid**

If a is the radius of a fixed circle and b is the radius of a smaller rotating circle, the parametric equations of the hypocycloid are x = (a − b) cos &thgr; + b cos [(a − b) &thgr; ]b

y = (a - b) sin &thgr; - b sin [(a - b) &thgr; ]b.