Can an ellipse's focal points be outside the ellipse? I have tried googling this, but without any good explanations or answers.(adsbygoogle = window.adsbygoogle || []).push({});

According to my calculations, the focal points of the ellipse defined by [itex] x^{2} + \frac{y^{2}}{4} = 1 [/itex] are [itex] (-\sqrt{3},0) (\sqrt{3},0)) [/itex].

I maybe wrong of course, but does this mean that the focal points of an ellipse can indeed be outside the ellipse?

BiP

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# Conic sections: Can focal points be outside the ellipse?

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