# Arduino Natural Log

In this tutorial, we will discuss how to take the natural log of a given number using the `log()`

function in Arduino.

## Calculate Natural Log of a Number Using the `log()`

Function in Arduino

To take the natural log of a given number, you can use the `log()`

function present in Arduino. This function takes an input argument of type `double`

which contains the given number and returns the natural log of that number. For example, see the below code.

```
#include <math.h>
void setup(){
double number = 30.5;
double logOfNumber = log(number);
}
```

In the above code, `number`

is a variable of type `double`

to store the given number and `logOfNumber`

is a variable of type `double`

to store the result of the natural log. You can change these variables according to your given number. If you want to take the log of a number in base 10, you can use the `log10()`

function.

```
#include <math.h>
void setup(){
double number = 30.5;
double logOfNumber = log10(number);
}
```

In the above code, `number`

is a variable of type `double`

to store the given number and `logOfNumber`

is a variable of type `double`

to store the result of the natural log. You can change these variables according to your given number. Do not forget to include the `math.h`

library before you use these functions because these functions belong to this library.