# Math Help - probability distribution function

1. ## probability distribution function

2. This is a lognormal distribution with $\sigma=1$
Log-normal distribution - Wikipedia, the free encyclopedia
I guess you need to just differentiate r(x) via the quotient rule to decide which is correct.

3. hi.. i tried this differentiating this as you had said, but was unable to get a meaningful result. The expression just got complicated and complicated. (Infact I doubt I even differentiated it properly)