Thanks for your help
...I can tell from the looks of it that it's a fairly simple question, but haven't done high school maths in...well, 5 years
Do I simply plug p=A/r back into dP/dr....it seems a little too simple
This was my try:
ρ = A/r
dρ/dr = –A/r^2
dP/dr = – GMρ / r^2
= – (G x M x –A/r^2) / r^2
= (G x M x A/r^2) / r^2
= GMA
Ps = 0
(Ps – Pc)(rs – rc) = (0 – Pc) / r
= –Pc / r
–Pc / r = GMA
Pc / r = – GMA
Pc = – GMAr