This tool is designed to provide the values of  along its level curves (contours). The contour map is generated by the contourplot command in the plots package.

Enter the expression for .

Bound the plot window by providing endpoints for the  and  ranges.

Provide either a number of contours to be drawn (the default is 8) or specify function values (c) for which a contour is to be drawn.  (After clicking the appropriate radio button, to its right enter a comma-separated sequence of one or more such values.)

Select a grid density:  is evaluated on an n × n grid, where  is the default (Grid density = 1). As Grid density increases to 6, n increases from 26 to 50, 60, 70, 80, and 100, respectively.

Click on the Contour Plot button to obtain the contour map, or to update the graph after the Grid density has been changed.

Click on the contour map itself with the Click and Drag Manipulator ( ) , available from the Plot menu or plotting toolbar, to obtain the value of  at that point in the plane. Click-and-drag to see a continuous update of the function values as the probe is moved across the plane.