Multimedia: Conic Sections



Ellipse: Sum of distances
from the foci is constant
(182K)


Conic Sections Defined by Eccentricity
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Geometer's Sketchpad version (GSP 4 required)

Conic Sections Defined by Eccentricity
1. Move the slider for eccentricity and see what kind of conic section you get.
2. Move the focus to see what impact that has on the figure.
3. Move a point on the directrix to show that no matter what point is taken on the curve, the ratio of the distance to the focus over the distance to the directrix always equals the eccentricity.