Nephroid curve as an envelope
- Zoltán Kovács
Equation of the nephroid curve is a sixth order algebraic curve, in this example. It is constructed by mirroring parallel rays to the edge of the circle.
- Drag point C to control the light ray. Note that the mirror ray is a tangent of the nephroid curve. You can try to switch tracing on by right-clicking on the mirror ray.
- You may drag point B to change the radius of the circle. (It will take a while for GeoGebra to recompute the nephroid curve with the new parameters.) There will be probably problems when the coordinates of B are not integers since numerical errors will occur. It is possible to use zooming in and out (Shift + mouse wheel).