Parabolic reflectors

15.4 Outline

1. Introduction
   1. definition
   2. model
2. Geometric definition of conic sections
   1. parabola
      1. focus
      2. directrix
      3. axis
      4. vertex
   2. ellipse
      1. foci
      2. major axis
      3. center
      4. minor axis
   3. circle
      1. center
      2. radius
   4. hyperbola
      1. transverse axis
      2. center
      3. conjugate axis
3. Algebraic definition of conic sections
   1. general form
      1. first-degree equation