Exercise 23.2.1 Verify that the variance of ln r in period k equals 2 k (k1) t.

Exercise 23.2.1 Verify that the variance of ln r in period k equals σ2 k (k−1)t.

(Consistent with Eq. (23.3), the variance of ln r (t) equals σ(t)2t in the continuoustime limit.)