Conic sections

In Mathematics, a conic  is a curve obtained by intersecting a cone and a plane.There are three types of conics - ellipse, parabola and hyperbola.

The graph of a quadratic equation  in two variables is always a conic section in a cartesian coordinate system though it may be degenerate, and all conic sections arise in this way. The equation will be of the form
Ax^2 + Bxy + Cy^2 + Dx +Ey + F = 0 with A,B and C not all zero.

Conic section equation:If the focus is () and the directrix is ax+by+c=0 then the equation of the conic section whose eccentricity =e is given as
(x−)2+(y−)2=e2 .(ax + by + c)^2/(a^2 + b^2)