A property of logarithms is that $\displaystyle \log_a x = \frac{\log_b x}{\log_b a}$ for all bases $a, b > 0, \neq 1$.
When $b = e$, this becomes $\displaystyle \log_a x = \frac{\ln x}{\ln a}$.

a) Using this identity, find the derivative of $y = \log_a x.$

b) Find the derivative of $y = \log_{3} x.$