Problem on relative volatility

Question

In vapor-liquid equilibrium the relative volatility α_ij is defined to be the ratio of the separation or K factor for species i to that for species j, that is,

 α_{ij =} K_i/K_{j = (}y_i/x_i)/(y_j/x_j)

In approximate distillation column calculations, the relative volatility is sometimes assumed to be a constant (independent of composition, temperature, and pressure). Test this assumption for the ethanol-ethyl acetate system using the following data:

RT ln γ_i = 8.163 x_j² KJ/mol

lm P^vap_EOH = (-4728.98/T) + 13.4643

lm P^vap_{EOH =} (-3570.58/T) + 10.4575