AP®︎ Precalculus: Topic 2.9 Practice Test

Essential Knowledge: 2.9.A.1

The logarithmic expression $\log_b c$ is equal to, or represents, the value that the base $b$ must be exponentially raised to in order to obtain the value $c$. That is, $\log_b c = a$ if and only if $b^a = c$, where $a$ and $c$ are constants, $b > 0$, and $b \ne 1$. (when the base of a logarithmic expression is not specified, it is understood as the common logarithm with a base of 10)

Essential Knowledge: 2.9.A.2

The values of some logarithmic expressions are readily accessible through basic arithmetic while other values can be estimated through the use of technology.

Essential Knowledge: 2.9.A.3

On a logarithmic scale, each unit represents a multiplicative change of the base of the logarithm. For example, on a standard scale, the units might be 0, 1, 2, ..., while on a logarithmic scale, using logarithm base 10, the units might be $10^0$, $10^1$, $10^2$, ....