Use Itos Lemma to evaluate d S 1 . For the following four problems, use Itos Lemma

Use Itˆo’s Lemma to evaluate d^S−1.

For the following four problems, use Itˆo’s Lemma to determine the process followed by the specified equation, assuming that S(t) follows 

(a) Arithmetic Brownian motion, equation (20.8); 

(b) A mean reverting process, equation (20.9); and 

(c) Geometric Brownian motion, equation (20.11).