This post lists the important functions available in the “math.h” library of C with their examples. Before continuing, you must know that we need to include the “math.h” library while compiling our program by using **-lm** (`cc -c filename.c`

` cc -o filename filename.c -lm`

).

Function | Description | Example |
---|---|---|

sqrt(x) | square root of x | sqrt(4.0) is 2.0 sqrt(10.0) is 3.162278 |

exp(x) | exponential (e^{x}) |
exp(1.0) is 2.718282 exp(4.0) is 54.598150 |

log(x) | natural logarithm of x (base e) | log(2.0) is 0.693147 log(4.0) is 1.386294 |

log10(x) | logarithm of x (base 10) | log10(10.0) is 1.0 log10(100.0) is 2.0 |

fabs(x) | absolute value of x | fabs(2.0) is 2.0 fabs(-2.0) is 2.0 |

ceil(x) | rounds x to smallest integer not less than x | ceil(9.2) is 10.0 ceil(-9.2) is -9.0 |

floor(x) | rounds x to largest integer not greater than x | floor(9.2) is 9.0 floor(-9.2) is -10.0 |

pow(x,y) | x raised to power y (x^{y}) |
pow(2,2) is 4.0 |

fmod(x) | remainder of x/y as floating-point number | fmod(13.657, 2.333) is 1.992 |

sin(x) | sine of x (x in radian) | sin(0.0) is 0.0 |

cos(x) | cosine of x (x in radian) | cos(0.0) is 1.0 |

tan(x) | tangent of x (x in radian) | tan(0.0) is 0.0 |

## Examples

```
#include <stdio.h>
#include <math.h>
int main()
{
printf("%f\n",sqrt(10.0));
printf("%f\n",exp(4.0));
printf("%f\n",log(4.0));
printf("%f\n",log10(100.0));
printf("%f\n",fabs(-5.2));
printf("%f\n",ceil(4.5));
printf("%f\n",floor(-4.5));
printf("%f\n",pow(4.0,.5));
printf("%f\n",fmod(4.5,2.0));
printf("%f\n",sin(0.0));
printf("%f\n",cos(0.0));
printf("%f\n",tan(0.0));
return 0;
}
```

Output

`3.162278`

54.598150

1.386294

2.000000

5.200000

5.000000

-5.000000

2.000000

0.500000

0.000000

1.000000

0.000000