Pe quantity when : <a = 0. 
+ of Central Forces. . 377 
sci e = =P? prcelsy an infinite 
eet, th Xe > stele te 
’ & 
r ‘P? 
But if the body begin to afcend, ‘the ereateft 
height atewhich it can arrive may r be found, 
by making p=y;. at which time | it comes to, 
an apfe. : 
Cor. 1. If n==o, or the facto be ee" oe ' 
at all diftances from the centre, then p=, 
Nek = 1 Ke ste 
‘but g=s* XS 
2 
Vr oy ag 
° " sP r? ° 
ft i fi So = 
erefore, by fubftitution, p: ne acaeaey 
the equation of the curve defcribed » by the 
body. % 
- Likewife, ‘it ‘will eafily appear, that a ea 
> 
sPr? I 
The ese 
yt 
for Rade teat the oe will be found'to > bd 
Past ot xry ray Pp This equa- | 
xt: Py 
tion 3 three real roots, as is evident from 
the latter part of the note in the propofition: two 
- of them are pofitive and one ‘negative; for they 
Jaft term of the equation is politive. The nega- . 
: ee ea 8 SE. 
