4 8 



Ellery W. Davis 



The foci are all complex and the representative vectors join the 

 foci of the black ellipse to the corresponding foci of the blue 



Y 



-X 



Fig. 44. 

 ellipse. Gjj Go are foci of a supplementary hyperbola 



""2 



y 



(2 + 2iy (1 + %)■ 



= 1. 



The companion hyperbola, which is really a part of the ellipse 

 under discussion, is 



x 2 _ 2 



(TT^) 2_:y " =I ' 



the blue constituent coinciding with the x-axh. 



Y 



