3. It is known that when an individual's preference exhibits constant absolute risk aversion, i.e. u(x)=exp(Ax), and when a random variable X is normally distributed, i.e. XN(,2), then the certanty equivalent of the expected utility is given by E[X]21Var(X), or equivalently, exp{Ax}(x)dx=exp{A(21A2)} where (x) is a probability density function of N(,2). Prove this fact