Proving (∂T/∂V)s = -(∂P/∂S)v from the first law

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Homework Statement



First law can be written dU = TdS - PdV where the internal energy U may be written in terms of any two of T,P,V,S.

I have to show that (DT/DV)s = -(DP/DS)v

where D is partial d, and the subscripts s and v mean hold those constant..

Homework Equations





The Attempt at a Solution



Not really sure how to proceed at all?
 
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This is one of the Maxwell relations.
If you have a function
[tex]f(x,y)=\left( \frac{\partial f}{\partial x} \right)_y dx + \left( \frac{\partial f}{\partial y} \right)_x dy = A dx + B dy[/tex]
then, according to
[tex]\frac{\partial}{y} \left( \frac{\partial f}{\partial x} \right) = \frac{\partial}{\partial x} \left( \frac{\partial f}{\partial y} \right)[/tex]
you have
[tex]\left( \frac{\partial A}{\partial y} \right)_x = \left( \frac{\partial B}{\partial x} \right)_y[/tex]