Definition of Hyperbola
Points A and B are the foci of the Hyperbola below.
Point D is the center of the Hyperbola below.
Point E lies on the Hyperbola.
Move points A or B to change the Hyperbola below.
Then move point E about the Hyperbola.
d1 is the distance from focus A to point E.
d2 is the distance from focus B to point E.