# Mathematical Functions

This chapter describes basic mathematical functions. Some of these functions are present in system libraries, but the alternative versions given here can be used as a substitute when the system functions are not available.

The functions and macros described in this chapter are defined in the header file ``gsl_math.h'`.

- Mathematical Constants
- Infinities and Not-a-number
- Elementary Functions
- Small integer powers
- Testing the Sign of Numbers
- Testing for Odd and Even Numbers
- Maximum and Minimum functions
- Approximate Comparison of Floating Point Numbers