### 5.3 - Reference - The eleven built-in functions

Mathematicians have defined literally hundreds of functions.
(See the *Handbook of Mathematical Functions*, by Abramowitz and Stegun,
for definitions of many of them.)
The eleven most useful functions are built into the Algebra Coach. They are:
For each of these functions we will:
- explain why the function is important
- state the domain and range of the function
- show a graph of the function
- list special values of the function
- give an algorithm to calculate the function
- show how to extend the function to the complex numbers
- explain how to use the function in the Algebra Coach