# Predefined functions

You need to have the` #include <math> `

directive at the top of your
program to use these. All parameters and return values are of type
`double`

.

Function |
Description |

`sqrt(x)` |
square root |

`sin(x)` |
trigonometric sine of `x` (in radians) |

`cos(x)` |
trigonometric cosine of `x` (in radians) |

`tan(x)` |
trigonometric tangent of `x` (in radians) |

`exp(x)` |
exponential function |

`log(x)` |
natural logarithm of `x` (base e) |

`log10(x)` |
logarithm of `x` to base 10 |

`fabs(x)` |
absolute value (unsigned) |

`rint(x)` |
round `x` to nearest integer |

`pow(x,y)` |
`x` raised to power `y` |