Compute the specific heat C v = U/T, with U = Z/ = (F)/, for the Ising

Compute the specific heat C_v = ∂U/∂T, with U = −∂Z/∂β = ∂(βF)/∂β, for the Ising model in the cases T < T_c and T > T_c and show that there is a discontinuity at T_c.