Im doing thermodynamics and my professor is terrible and doe

Im doing thermodynamics and my professor is terrible and doesn\'t really teach very well. The problem I am on has to do with isentropic air. How do I know when a problem has variable specific heat or constant specific heat so I can figure out how to solve the problem with the appropriate method?

Solution

when u have provided with the equation of specific heat is the function of tempreture. then it is variable.

otherwise it is constant.or u have to asked to find out the specific heat at a particular tempreture so it is variable

and sometimes when u work with the real gas it may be variable.