Search Results for “foci”

Trammel foci
Altering |AB| and |AC| changes the ellipse. Can you find a relationship between |AB|, AC| and |DE|, the distance between the foci?
Ellipse as locus of circle center
Take two overlapping circles. Examine the locus of the center of the circles tangential to both. It seems to be an ellipse with foci at the centers of the two circles. Prove it.