From "some proof that uses the definition" of a derivative, I understand that:
$$\ (\log_a x)' = \frac{1}{x \ln a} $$
Since this is the case, I should also be able to prove that:
$$\ \left(\frac{\ln a}{\ln a}\right)' = \frac{1}{x \ln a} $$
So I did some stuff with $\ \left(\frac{\ln a}{\ln a}\right)'$ until I managed to get to:
$$\ \frac{1 - \frac{x (\ln a)' \ln x}{\ln a}}{x \ln a} $$
Which would mean, if I'm not mistaken, that:
$$\ \frac{x (\ln a)' \ln x}{\ln a} = 0 $$
Can someone explain how this is possible to me, or if I made a mistake of some kind?