Conic section
A conic section is any of several types of figures. These figures all are easily describable in terms of explicit equations in two variables with degree 2. The name conic section refers to the fact that, given two right circular cones placed tip to tip, all the conic sections can be formed by cutting through with a plane. The resulting imprint on the plane is either a circle (caused by cutting parallel to the base), ellipse (caused by cutting at an angle less than the angle of the cone), parabola (cutting at an angle equal to that of the cone) and hyperbola (caused by cutting at a greater angle).
