From GeoGebra Manual
- ClosestPoint[ <Path>, <Point> ]
- Returns a new point on a path which is the closest to a selected point.
Note: For Functions, this command will return the point vertically in line rather than the nearest point
| Following text is about a feature that is supported only in GeoGebra 5.0.
Note: From GeoGebra 5, these syntaxes will work as well: ClosestPoint[ <Region>, <Point> ], ClosestPoint[ <Line>, <Line> ]