4. In a two good world, a consumer has the utility functionU(x; y) = u1(x) + u2(y);where u1′ > 0; u2′ > 0; u1”< 0; and u2'' < 0: You know nothing else about the utilityfunction (that is, you do not know the speci?c functional form). Determine the signson the comparative statics terms