1. The problem statement, all variables and given/known data If dU=TdS-PdV then (dS/dV)T=(dP/dT)V the T and V at the end means that T and V are constant How did they get this identity? It came from a thermodynamics hence for their notations. I have tried ways like rearranging but it dosen't seem to work. I think it has something to do with exact differentials.