Question

What are the foci of an ellipse?

Answer 1

Foci of an ellipse are two fixed points on its major axis such that sum of the distance of any point, on the ellipse, from these two points, is constant.

Explanation:

In fact an ellipse is defined to be a locus of points such that sum of the distance of any point from two fixed points is always constant. These two fixed points are called foci of an ellipse