3. [In class, we noted that the consumer will spend all their money if they have i11- creasing preferences. Here, we give a calculusbased condition for the consumer to spend all their money, that doesn't assume more is always better. The c011- dition is a stronger version of what is sometimes called \"local non-satiation\" .] Let :1: E X , and let M'Ui denote the marginal utility for good '5' E {1, 2} at 3:. (a) Suppose some good i has M'UE- 75 0 (it could be positive or negative), and suppose the consumer is not spending all her money at bundle :1: (that is p - :1: 0 if EMU;