[ 524 ]■ 



This value of a, as was (hewn above, anfwers the conditions 

 of the problem. 



XT ^* J^J — z\ 



Now X z= z s, a — — ,y = z cs., a — zL 



r r* 



whence y^ = z'^ — — = r x — »* , which is the equat. to the 

 circle, as before found. 



2. Let s,a=—, then cs, a =\ i — — 



W r4 



and a — 



2 Z Z 2 Z Z 



r^rY — Z4- fr4 — z4 



V 1 W ^ 



Hence 2 r a Ar^ — x» —4^2: 



,/ rrz 



2r air* — 5r»^ = J'2^i x4r» 

 confequently the fluent of J- ^ ^ r*—zij = — r3 X 4|^— 5 ^ when 



and 



I 



