Let , be a parametric curve. The rate of change of the position is given by , and is called the velocity at , . The computer may help us understand the velocity by drawing the line segments joining with , as ranges over equally spaced points of the interval . For example, the velocity along the circle , , is represented as:
The procedure follows these steps in Maple:
> x:=cos(t);
> x1:=diff(x,t); > y1:=diff(y,t);

The velocity along the epicycloid
appears as:
¡@
The velocity along the epicycloid
appears as:
¡@
The velocity along the cycloid
appears
as:
¡@