# Lisp Parabola

This is pretty simple. Its a start. Func1 defines the equation ax^2 + bx + c with the specific values of a b and c and returns the value when passed the current value of X.  C:para calls the parabola function and sets the x minimum, maximum and x increment.

screenshot from the visual lisp editor.

if instead of unconnected lines, we want to graph with a 2D Polyline, the command is PLine, it takes the same point list. We start the Pline command with the first point, then enter the loop and calculate the next point each time through the loop, leaving the command processor running and just feeding it one point each time.

For graphing polar equations – Polar Coordinates – P(R,Ɵ) – A point is defined by how far it is from the origin (R – Radius) and what angle (Ɵ – Theta) a line from the origin to the point makes with the horizontal axis. (I am using A for angle instead of Ɵ in the code)

To change the command from separate lines to connected polyline, we start the pline command outside the loop and only calculate one point in the loop, just as for the rectangular cartesian program.