Question

Find the constant sum for an ellipse with foci F1 (0, -12), F2 (0, 12) and the point on the ellipse (9, 0).

Answer 1

As best I remember, you should get the distance from F1 to P(9,0) and add it to the distance from F2 to the point on the ellipse P(9,0). Just use the distance formula for each calculation and see what you get.

Answer 2

For the constant sum I got 30

Answer 3

The sum notion originates from the definition of an ellipse as the set of points in a plane, the sum of whose distance from two fixed points (foci) is a constant greater than the distance between them (the foci).

Answer 4

I got 30, also.

Answer 5

Great thanks