The hyperbola
A hyperbola is the set of points in a plane whose distances from two fixed points, called foci, have a constant difference. As you slide the slider, this definition is illustrated. (This feature is only available if the "Foci on x-axis" checkbox is selected.) The value of this constant difference is the distance between the hyperbola's vertices. You can drag point P anywhere on this hyperbola to see the illustration.
This interactive figure displays the graph of a hyperbola having center at the origin and foci and . Here, a = the distance between the hyperbola's center and a vertex, c is the distance between the center and a focus, and .
Developed for use with Thomas' Calculus, published by Pearson.