Ellipse

Ellipse

An ellipse is a conic section formed by cutting through a cone on an angle. More specifically, it is defined as the locus, or set, of all points P such that the sum of the distances from P to the to foci (s. focus) is a constant. Ellipses tend to resemble "flattened" circles. They occur in nature as well: as was proven in Kepler's Laws, the planets all revolve about the sun in elliptical, not circular, orbits with the sun at one of the foci. To draw an ellipse with two pushpins, a rubber band, pencil and paper, stick the pushpins in the paper (these will be the "foci"), the rubber band around the pins, and trace out (please finish description, wording gets awkward after this for me).

The general equation of an ellipse with semi-minor and -major axes a and b and center C(h,k) is , or, when centered at the origin, </math>.