parabola(Point, Line) or parabola(Point, Realk) or parabola(Expr)
Draws a parabola, given a focus point and a directrix line, or the vertex of the parabola and a real number that represents the focal length
parabola(GA, GB) draws a parabola whose focus is point A and whose directrix is line B.
parabola(GA, 1) draws a parabola whose vertex is point A and whose focal length is 1.
parabola(x-y^2+y-2) draws the graph of the parabolic equation x=y^2-y+2
parabola — Discussion