circle
A circle is all points in a plane that are a fixed distance from a fixed point in the plane.
ellipse
An ellipse is all points in a plane where the sum of the distances from two fixed points is constant.
hyperbola
A hyperbola is defined as all points in a plane where the difference of their distances from two fixed points is constant.
parabola
A parabola is all points in a plane that are the same distance from a fixed point and a fixed line.
system of nonlinear equations
A system of nonlinear equations is a system where at least one of the equations is not linear.