Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Focus of an ellipse vs. cone

  1. Dec 7, 2008 #1
    An ellipse is a conic section. If you construct an ellipse using a cone, does the axis of the cone cross through one of the foci of the ellipse?

    if so, how can this be shown mathematically?

    This is just purely out of curiosity.
     
  2. jcsd
  3. Dec 7, 2008 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi TheFerruccio! :smile:
    Sorry … noooo.

    The foci are the points at which the Dandelin spheres touch the plane of the ellipse (or hyperbola) … see the PF library entry " conic " for details. :smile:
     
  4. Dec 7, 2008 #3
    that makes sense. So, does the axis of the cone have any geometric significance in this case beyond just what was described?
     
  5. Dec 8, 2008 #4

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Not that I know of … :blushing:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Focus of an ellipse vs. cone
  1. An ellipse question? (Replies: 7)

  2. Equation of Ellipse (Replies: 2)

  3. Ellipse from cone (Replies: 3)

  4. Ellipses on spheres (Replies: 0)

Loading...