4.7 Tangent Lines to Point Conics
Each problem I solved became a rule which served afterwards to solve other problems.
—Rene Descartes (1596–1650)

         Points P and P' are two points of a point conic which may be taken as the centers of the pencils of lines for the projectivities defining the point conic. Note that the two lines PH and PH'  that are projectively related to the line PP' both appear to be tangent to the point conic. (H is the center of homology.)

4.7 Tangent Lines to Point Conics
 
     
© Copyright 2013 - Timothy Peil