3. DERIVING DENIAND. For each of the following utility functions, derive the expression for the demand for good X, showing how X depends on price PX and income M. Assume that Y is a composite good with price PY = 1 and focus your attention on interior solutions. a) U[X, Y] = 2+ 4V? b) U[X,Y] = X(Y + 1) c) U[X, Y] = min{X, ZY}