Hey what is the directrix when talking about an ellipse?(adsbygoogle = window.adsbygoogle || []).push({});

I found a book that finally shed light on what eccentricity was, but there's still no mention of what the directrix is.

To be honest, it doesn't even explain eccentricity but I intuitively understand it, however the directrix is something that I don't understand with reference to an ellipse, nor how to find it nor why anybody wants to.

Perhaps you could shed some light on how to go about finding it.

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# Directrix when talking about an ellipse?

**Physics Forums | Science Articles, Homework Help, Discussion**