is.] ////. A. /./.// 



nuny poinU an desired may be construct**! ; a smooth 

 connecting these points in approximately an e-llipne. 



4. 





. '. 



Fie. KM. '' 



(ff) Construction by a continuously moving point. Fi x two 



i?ht pins at the foci, and over them place a loop of string, 



equal in length to the major axis plus the distance between 



.. Press a pencil point against the cord so as to 



keep it taut. As the pencil moves around the foci, it will 



trace an ellipse. 



EXERCISES 

 1 Construct an ellipse with semi-axes 8 and 6. 



2. Construct an ellipse with semi-axes 6 and 12. 



3. Construct an ellipse with the distance between the foci 24, and 

 the minor axis of length 10. 



4 Write the equation of the polar of the left- hand focus of the 

 + =1. What line is this? 



5. My employing equation [59], find the tangent to the ellipse 

 ; j- f J5 y* = 400, and passing through the poi 



6. By the method of Kx. 17, p. 226, show that an ellipse is concare 

 its center. 



.rough what point of the ellipse + = 1 must a tangent and 

 be drawn, to form with the jntxi* an isosceles triangle? 



8. Write the equations of the tangent and normal at the posit ire end 

 thelatusn i,e ellipse * + 4y = 4. Where do these lines out 



JMUUS? 



v AX. OBOM. 10 



