Homework Help: Partial Derivatives Again

1. Mar 1, 2009

MathNoob123

1. The problem statement, all variables and given/known data
(e^0.16)/(1+e^-0.3y)
I am suppose to find the fy
of this

2. Relevant equations
A bit trickier than the last prob i posted

3. The attempt at a solution
What I did:
Since (e^0.16) is a constant, I left it just like that and took the derivative of e(-0.3y)

my outcome: (e^-0.16)/(-0.3e^-0.3y)

2. Mar 1, 2009

phreak

You can't just take the derivative of the bottom and leave it like that. That's equivalent to saying that the derivative of 1/f is 1/f', which is false. First of all, find the derivative of 1/x. Now use substitution and the chain rule.