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Niles
Oct13-07, 05:48 AM
1. The problem statement, all variables and given/known data
The law for an ideal gas is given by P = n*R*T/V. In our case, n and R are constant, so P = f(V,T).

I have found dP/dT, dT/dV and dV/dP. I have to find the result when these three differentials are multiplied with eachother.

3. The attempt at a solution

I get -1 - can you guys confirm this? And what does this mean?

Hurkyl
Oct13-07, 07:47 AM
Looks right to me. This is true for any three variables related by a differentiable function.

Niles
Oct13-07, 09:08 AM
I see.. does it have any specific meaning for an ideal gas?

Niles
Oct14-07, 02:10 PM
I have searched Wikipedia - I haven't found anything. Can you help?

Hurkyl
Oct14-07, 02:37 PM
I cannot think of any meaning that goes beyond the literal interpretation of the operations.

e.g. it suggests that, at least on tiny scales, you can compute the relationship between P and V along an isotherm by instead looking at how T and P relate along an isochore and how T and V relate along an isobar.

learningphysics
Oct14-07, 04:30 PM
Found this link on wikipedia. But it doesn't go through much except an informal derivation:

http://en.wikipedia.org/wiki/Cyclic_chain_rule