II] in t.g 



.ml y, yi, t*qu.u takes the indeterminate form 



jr-jr- (*-'.> (*) 



null (.minuteness arises because account has not yet 

 ten of the path (or direction) l>\ \\hult /'. shall 

 oach PH and itdtsa; immediately if the r..niiti..n 



/'. is to approach /', iilont/ the circle (1) is intr. ..lured. 

 inoe the fixed jH.ini 1\ i> <>n th.- m, :,- ( i ;, therefore 



since /V while approaching P|, always remains on circle 

 A therefore 



ic , + y i .r j ; ... (6) 



subtracting equuiimi (4) fmm equation (5), 



ig this result in equation < J ) gives 



is the equation of the secant line LM of the given 



The difference between equations (2) and (0) oonstots In Ink: no mat- 

 where the point* (z l% y ( ) and (z,, y,) may he, equation (2) repmenu 

 traight line paaing through them ; hut equation (6) IB the equation of 

 line through theae potato only when they are on the circle r* + jr 8 = f 4 . 

 word*, equation (9) to the equation of the line pawing through any 

 ato whatever, while equation (0) to the equation of the line 

 any two potato on the circumference of the circle. 



TAX. A*. OKOM. 10 



