//'-A. 



'I tltre are two tangenU to an 



parallel to any given line; and lno (Art. 125), that 

 two tangenU to an ellipse from any external point. 



144. The sum of the food distances of any point on an 

 ellipse is constant ; it is equal to the major axis. 



The ellipse j + J~l 1m* r the point* 



f.aC-o*, 0) and *>,<>, 0); 



.rf-V. . 110.) 



/' i(y t , y,) be any point ..n tlu curve, HO that 



.r'., 



-a ; --*-V: 



FjP, a 4- a*. 



