# Differentiation Problem

#### macro90

##### New Member
This is a differentiation problem that I stumbled across while trying to calculate log-likelihood estimate, so it is related to statistics.

I'm having problems with the differentiation below

I can see how the
is obtained using the product rule, but I don't see how the term after that,
, was obtained. Shouldn't that term be
instead? See how I got this term. What have I done wrong?