Question 6 Suppose S follows geometric Brownian motion process, i.e. dS/S= udt+o dz, where z follows the Wiener process. Find the stochastic processes followed by (i) y=es, and (ii) y = S. In each case, you need to express the drift rate and the volatility in terms of y rather than S. (Those students who are unfamiliar with calculus, please note d(es)/dS =es and d(S")/dS =n S-t.)