"Even if the programs differ in their conceptual and ergonomic designs, they share
- a dynamic model of Euclidean school Geometry and its tools (the dragmode),
- the ability to group a sequence of construction commands into a new command (macro-constructions),
- the visualisation of the trace of points which move depending on the movement of other points (locus of points)"
Using the above dynamic geometry software, draw the enveloppe of the parabola of focus A and directrix the line l.