Problem 2.18. Compute the heat capacity at constant magnetic field CH,n, the susceptibilities XT, and XS,, and the thermal expansivity Q for a magnetic system, given that the mechanical equation of state is M = nDH/T and the heat capacity is CM, nc, where M is the magnetization, H is the magnetic field, n is the number of moles, D is a constant, c is the molar heat capacity, and T is the temperature.