2. (a) What do you mean by Marginal rate of Substitution (MRS) and Law of Diminishing Marginal Utility? (b) Derive the Equi-Marginal Principle. What does it state? Can you generalize the principle? [ Hints: Show it for n commodities where, n = 1, 2, .. .. .. .m;] (c) The consumer has a utility function u(x,, x2) and s/he is assumed to maximize this utility, subject to the constraint that the amount she spends on the goods cannot exceed the income she has available, m. If we assume consumer's preference are such that the utility function takes the Cobb- Douglas form and the constraint followed by max u(1,x) =x1x2 subject to Pixi + PzXz = m with 0