The conic sections and Apollonius circles

Authors

  • Jiří Blažek Pedagogical Faculty, University of South Bohemia, České Budějovice
  • Pavel Leischner Pedagogical Faculty, University of South Bohemia, České Budějovice

Abstract

If the conic is given by the focus of F, directrix d and the excentricity ε≠1, then it can be obtained as the envelope of Apollonius circles uF,H,ε, where Hd. Each of the circles uF,H,ε touches the conic at points that are the intersections of this circle with the line that is parallel to the major axis of the conic and passes through the point H. The equivalence of the common definitions of conics (based on directrix or on constant sum or difference of distances) appears as a simple consequence of this approach.

Published

2019-08-28

How to Cite

Blažek, J., & Leischner, P. (2019). The conic sections and Apollonius circles. MATHEMATICS–PHYSICS–INFORMATICS, 28(3), 175–185. Retrieved from https://mfi.upol.cz/index.php/mfi/article/view/456

Issue

Section

Mathematics