4. (1.5 p) Helen has elementary utility function u , where u > 0 and u"

4. (1.5 p) Helen has elementary utility function u, where u' > O and u" < O, and her initial wealth equals X. She can participate in a lottery, where he can gain or loss a with equal probabilities. (a) Derive an implicit function for the risk premium (explain every step carefully). (b) How the risk premium would change if a goes up?