How to use
Enter functions x1(t) and y1(t) in the text input fields marked "x1(t)=" "y1(t)=".

 Example: x1(t)=cos t, y1(t)=sin t

Click the "Graph" button (this button also refreshes the graph).

To see two parametric curves graphed simultaneously:

Enter the second set of functions x2(t) and y2(t) in the text input fields marked "x2(t)=" "y2(t)=".

Click (to its "on" state) the check box next to these input fields.

Click the "Graph" button.

 Example: x1(t)=cos t, y1(t)=sin t; x2(t)=t-1, y2(t)=1-t

Up to three curves can be graphed simultaneously

To remove a function from the graph, click (to its "off" state) the check box next to the associated text input fields and click the "Graph" button to refresh.

To erase the graph and all input fields, click the "Clear" button.

 Line: x1(t)=t-1, y1(t)=1-t

 Circle: x1(t)=cos t, y1(t)=sin t

 Polar Curve: x1(t)=cos 5t cos t, y1(t)=cos 5t sin t

 Cycloid: x1(t)=t-sin t, y1(t)=1-cos t

Other Notes
The graphs of the equations are color-coded, corresponding to the colors of the labels marking the text input fields: the graph of (x1(t),y1(t)) is blue, (x2(t),y2(t)) is red, and (x3(t),y3(t)) is green.