The Universe of Conics

Descartes' theorem

In geometry, Descartes' theorem states that for every four kissing, or mutually tangent, circles, the radii of the circles satisfy a certain quadratic equation.

Coniques focales

En géométrie, deux coniques Γ et Γ’ sont dites focales si elles sont situées dans des plans perpendiculaires et si les sommets de l’une sont les foyers de l’autre.

Confocal conic sections

In geometry, two conic sections are called confocal if they have the same foci.

Confocal conic sections

In geometry, two conic sections are called confocal if they have the same foci.