l.'o It) 





/' .\v a 



t line Jf, and let 7' ; i 

 its other . mtn- 



the locus of equal i. < 1 ). If 

 int /'.. moves along the cm \ .- 

 unt il it comes into coincidence 

 /',. tin* limiting position nf these- 

 cant LM'M the tangent / 

 The equ tin- lint- /. J/ 





i.. .... 



If now P, approaches 7', until jr. - j 

 .issumes the iniletrnninate form 



. (8) 



V 



HP let mini lateness arises because account has nt 

 been taken of the path (or direction) by which P, shall 

 -ach P,, ami it disappears immediately if the condr 

 /' and P, are points on the conic (1) is introduced, 

 i u< i P, are on the conic 



therefore Ar? + By? + '2 GJT I 4- '2 Fy^C** 0, ... 

 ami 1 ; : + Byf + 2 Qxi -h 2/y, + C= 0, . 



i.-tinir n|iiaiioii (I) from njuati- transposing, 



'. .iinl rrarranu'in^ [ I , x I. :u.t! : -:.- . - 



], the result may In- \\rittm 



If tins valm- of 

 mult is 



hJfOH 



is substituted in equation < _ >. the 



r - j 



