Question

How do I find the foci of an ellipse?

Answer 1

wiki says: distance from the center C to either focus is f \(=\sqrt{|a^2-b^2|}\). (I put absolute values so you can forget about who is a and who is b).

Answer 2

the distance to a focus from the center of the ellipse is => \(\huge c = \sqrt{a^2-b^2}\)

Answer 3

both values squared will give positive anyway, and "a" is always bigger in an ellipse