Derivative of General Logarithm Function

Theorem
Let $\log_a x$ be the logarithm function to base $a$.

Then:
 * $D_x \left({\log_a x}\right) = \dfrac {\log_a e} x$

Proof
From Change of Base of Logarithm, we have:
 * $\log_e x = \dfrac {\log_a x} {\log_a e}$

from which:
 * $\log_a x = \log_a e \; \log_e x$

In this context, $\log_a e$ is a constant.

The result then follows from the above result and Derivative of Constant Multiple.