[wynn]

I have attached the equation which I have question with.
If we have a system that undergone a process with a change of volume, and we want to apply this equation, how do we calculated del P / del T if temperature and pressure of initial and final state are given? Do we simply the differences between them disregarding that the process is not isochoric?
And how do we determine the P after del P / del T is the pressure of system or surrounding?
I have always run into similar type of confusions in thermodynamic, and it is very frustrating. Please help.

Thank You