What's Wrong With My Answer?

moe darklight

1. The problem statement, all variables and given/known data

y = (3x)^x

(find y' )

2. Relevant equations

y = a^x
y' = (a^x)(ln(a))

and the chain rule

3. The attempt at a solution

3((3x)^x)(ln(3x))

rock.freak667

Take ln of both sides of the equation

lny=x*ln(3x)

Now use implicit differentiation

moe darklight

yes, that was the answer that was provided; but I don't understand why my answer is incorrect, given the fact that the derivative of a^x is (a^x)(lin(a)) and the formula seems to be of that form.

rock.freak667

I believe for that equation to work 'a' must be a constant.

moe darklight

O, thanks.