Logarithms

A logarithm is an exponent with a given base. Consider the equations below:

Key aspects of logarithms include:

  • a logarithm is the inverse function to exponentiation

  • in the simplest case, the logarithm counts the number of occurrences of the same factor in repeated multiplication; e.g., since 1000 = 10 × 10 × 10 = 103, the "logarithm base 10" of 1000 is 3

  • logarithms can be used to compress a scale of measurement

Rules

Following are mathematical rules for working with logarithms:

An Example

An example of the use of logarithms is displaying exponential growth, such as Moore’s Law: