Inverses of Exponential Functions

In 2.9 you met the logarithm as an operation: “what exponent?” Now we treat it as a function, $y = \log_{b} x$ (the logarithm with base b), and compare it with its partner $y = b^{x}$. Every feature of the exponential graph from 2.3 has a matching feature on the logarithm graph, because the two are inverses.