Constant Coordinate Curves for Elliptic Coordinates

This Demonstration shows curves of constant coordinate values for the elliptic coordinate system in two dimensions. These curves are semi-hyperbolas and ellipses, the latter having foci at . As you drag the locator in the plane, the curves are redrawn so they pass through that point. Holding the mouse over the curve shows which variable is constant along that curve, and holding it over the point gives the actual values of the variables. You can vary the interfocal separation, ; at the elliptic coordinates are equivalent to polar coordinates.