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.

F_{1}, F_{2} - 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

e^{2 }= a^{2 }- b^{2}

r_{1}, r_{2} - 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