Comparison of the true weight of the matter distribution in the midplane of the M33 disk, P_true, as from numerical computation of equilibrium models, to analytic expressions reported in this Appendix. In the left panel we plot the ratio of analytic approximations of midplane pressure P to the true pressure P_true for the case of no dark matter. In the right panel we can see similar ratios when dark matter has been considered in M33. According to color, P refers to P_hy, P_BR, and P_DE expressions across the M33 disk (see text for details).