Starting with = (1/cp) [T (v/T) p - v] and noting that Pv = ZRT, where Z

Starting with μπ = (1/cp) [T (∂v/∂T) p - v] and noting that Pv = ZRT, where Z = Z(P, T ) is the compressibility factor, show that the position of the Joule-Thomson coefficient inversion curve on the T-P plane is given by the equation (∂Z/∂T)P = 0.