Ellipse and its properties graph calculator

An ellipse is the locus of points on a plane where the sum of the distances from a moving point to two fixed points is a constant and this constant is greater than the straight-line distance between the two points. It can also be defined as the locus of points where the ratio of the distance to a fixed point to the distance to a fixed straight line is a constant less than 1. It is a type of conic section, i.e., the section of a cone and a plane. The ellipse plays an important role in Kepler's three laws of planetary motion, i.e., a star is one of the two foci of an ellipse.