QUADRATURE of the CONIC SECTIONS, &c. 30% 
known formule 
I 
2ab - = (ab s-+ ords)" + (abs — ord sy", 
I 
2 ord = = (abs + ord ges (ab s — ord sy, 
by proceeding as follows. Let each fide of the latter of thefe 
equations be divided by the correfponding fide of the former, 
the refult is 
T 
ai 7 5 
on a _ (abs+-ords) —(abs—ords) , 
ah I £ 
na (abs-+ord 5)" + (ab s— ord 5)" 
which expreflion is equivalent to this other one, 
s ab s + ord 5)" 
ee ley soe ) aoe 
Ait 
ab © i 
n (PP saoo 
ab s—ords +1 
abs-+ords 
abs—ords’ then, te- 
LeT us now put # for the fraction 
; a 5 
marking that ; = tan -, we have 
Vo. VI.—P. II. Qq an 
