11. Consider a process whose value changes every h time units; its new value being its old value multiplied either by the factor eσ

√

h with probability p = 12

(1 + μ

σ

√

h), or by the factor e−σ

√

h with probability 1−p. As h goes to zero, show that this process converges to geometric Brownian motion with drift coefficient μ and variance parameter σ2.