# Math 22 Derivatives of Logarithmic Functions

 Let ${\displaystyle u}$ be a differentiable function of ${\displaystyle x}$.
1.${\displaystyle {\frac {d}{dx}}[\ln x]={\frac {1}{x}}}$ for ${\displaystyle x>0}$
2.${\displaystyle {\frac {d}{dx}}[\ln u]={\frac {1}{u}}{\frac {du}{dx}}}$ for ${\displaystyle u>0}$