# Homework Help: Thermal Phys: Show (du/dP)|t = Pkv - (cp - cv)K/B

1. Sep 28, 2009

### StarTiger

For some reason this proof in thermal is tripping me up.

1. The problem statement, all variables and given/known data

Show that (du/dP)|t = Pkv - (cp - cv)K/B (problem 4-4 in Carter or 1.14 in Cheng)

2. Relevant equations

B = 1/v(R/P) = 1/T
k= -1/v(-RT/p^2) = 1/P

3. The attempt at a solution

You want to prove this generally, not just for the case of the ideal gas. Do you know the definitions of $C_P$ and $C_V$?