Conic Section
   A conic section may more formally be defined as the locus of a point P
   fixed line d called the conic section directrix (with F not on d )
   A conic section with conic section directrix at x=0 , focus at (p,0) ,
   The polar equation of a conic section with focal parameter p is given
   The pedal curve of a conic section with pedal point at a focus is
   section is a quadratic curve, which has general form
   of a conic section from five points lying on it is called the
   The general equation of a conic section in trilinear coordinates is
   coordinates alpha:beta:gamma , the conic section they determine is
   cuts the plane, only five can contain a conic section which is tangent
   Cone, Cylindric Section, Eccentricity, Ellipse, Ellipsoidal Section,
   Section, Spheroidal Section, Steiner's Theorem, Three Conics Theorem,
   Toric Section
   Weisstein, Eric W. "Conic Section." From MathWorld--A Wolfram Web
   Conic Section in the
   Tangent Lines to a Conic Section Tangent Lines to a Conic Section
   Tangent Lines to a Conic Section
   Conic Section Conic Section Conic Section