.1 VALYT1C <-/ U/ ;//;> 



i I'M. X. 169. 



<>f the intersection P of two tangents 



24. if the MI in of the eccentric angles of their points of contact is a 

 constant, equal to 2 a. 



25. if the difference of the eccentric angles be 120. 



26. Find (lie locus of the middle points of chords of an ellipse \vhirh 

 pass through a given point (A, /). 



27. Find the tangents common to the ellipse ~ + 

 circle x* -f y* = ab. 



1 and its mid- 



