ABSTRACT
Take a flashlight and shine it straight onto a wall. You will see a circle. Tilt the light, and the circle will turn into an ellipse. Tilt further, and the ellipse will become more and more elongated, and will become a parabola eventually. Tilt a little more, and you will have a
that cone with a plane (i.e., the wall). Thus, we have the name conic section for curves that are the intersections of cones and planes. (See Figure 9.1.)
The three curves, ellipses, parabolas, and hyperbolas, arise in many situations and are the subject of this chapter. The basic tools for handling them are nothing but the matrix theory developed earlier.
