So the origin is located in the center of the long axis, so the coordinates of point A are (7782.5,0) and the coordinates of point B are (-7782.5,0).
The F2 coordinate (7782.5-6371-439,0) is (972.5,0).
The square of the minor axis length is: 7782.5 * 7782.5-972.5 * 972.5 = 59621550.
So the equation is: x 2/7782.5 2+y 2/59621550 =1.