- Create axes.
- Place a point on the x-axis and measure its coordinates.
- Use the calculator to isolate the x-coordinate of the point.
- Use the calculator to create an expression for y(x).
- Select the x-coordinate and shift-select the y(x) value.
- Choose
*Plot as (x, y)*from the*Graph*menu. - Select the plotted point and shift-select the x-point.
- Choose
*Locus*from the*Construct*menu.

This technique assumes you want to plot Y as a function of X. You can obviously
measure things differently and plot X as a function of Y. If you change the Grid
to display a polar coordinate system (in the *Graph:Grid Form* menu),
*Plot as (x, y)* becomes *Plot as (r, theta)*, with which you can
plot polar functions as well. Check out the sample *Odds and Ends* sketch
which comes with Sketchpad 3 for ideas about plotting parametric functions.

Return to the Foyer.

*Sketches, scripts, and web pages by Bill Finzer
and Nick Jackiw.*