# Can't understand one step in derivation (partition function)

This is from self-study coursework rather than homework. I hope it's ok in this forum.

I'm following a statistical mechanics lecture on youtube, and the professor is deriving the average energy as a function of the partition function. He goes:

-1/Z dZ(beta)/d beta = -dlnZ(beta) / d beta

where Z(beta) is the partition function = e^{-(beta) E}.

I spent an hour trying to figure out why the LHS equals the RHS (from both directions, including using differentiation by substitution) but I just can't figure out how he does it.

Perhaps this is a really simple question (and if so, I apologies for my stupidity) but can anyone tell me how to go between the two steps?