Ellipse is a curve on a plane surrounding two focal points such that the sum of the distances to the two focal points is constant for every point on the curve.

F1, F2 - fixed points; foci, focal points of ellipse

A, B,C, D - vertices of ellipse

S - center of ellipse

2a=|AB| - major axis

2b=|CD| - minor axis

e - linear eccentricity

e2 = a2 - b2

r1, r2 - radial vectors of the point T

Created by Helena Halas, translated by Helena Halas and Iva Kodrnja - 3DGeomTeh - Developing project of the University of Zagreb