Drawing a Line Segment From a Point on a Curve to a Line
I'm dropping a line segment perpendicularly from a point on a parabola to the directrix.
I have used the segment command with the point P as one of the arguments and the other argument is an imaginary point on the directrix. (named "Directrix")
So I have g = segment (P, (x(P), y(Directrix))) but this doesn't work properly.
Then I tried to draw a line segment with a certain length because this is the other usage of the segment command. However how does the command know which direction to draw the line segment if only a point and length are the argument?
This is the syntax in the Wiki.
g = segment (P, y(P) - y(Directrix)) which doesn't work either.