# Logarithm

The ‘logarithm of $x$ to base $b$ is what you have to raise $b$ to the power of in order to get $x$. In symbols, $\log_b x=a \iff b^a=x.$ Here, $b$ is a positive real number other than $1$ and $x$ is a positive real number.

Being closely related to powers (indices), there are logarithm laws corresponding to the index laws.