Question

do the foci of ellipses always lie on the major axis?

Answer 1

I'd suggest you do Internet searches when you have questions like this one.

I did a search for "ellipse major axis" and came up with the following:

http://www.mathopenref.com/ellipseaxes.html

You could also do a search for "ellipse foci".

From what I can see, in http://www.mathopenref.com/ellipseaxes.html, the foci of an ellipse are always on the major axis (the longer axis) of the ellipse.

Answer 2

right, thanks