This demo displays the circle given by X(t) = (a,b) + (Rcos(t), Rsin(t)).
To change
(a,b), type the desired expression for (a,b) in the appropriate text box in the
control window and press Enter. To move the
point X(t_{0}) along the circle, or to change R, the radius of
the circle, use the arrow buttons ([<], [>], [<<],
[>>]), which have the same function as in the first two demos. As
in earlier demos, there are "Show entire curve", "Show position
vector X(t0)" and "Show Color Spectrum" options.