Parabola is the locus of the points in the plane that are equidistant from a fixed point and a fixed line.

F - fixed point: focus of the parabola

r - fixed line: directrix of the parabola

A - vertex of the parabola

d(A,F)=p/2 - focal length

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