# JavaScript Math.log1p()

The `Math.log1p()` method returns the natural logarithm of 1 plus the given number. It is equivalent to ln(1+p) in mathematics.

### Example

``````// calculate ln(1+p) of 1 which is equivalent to ln(2)
var value = Math.log1p(1); // ln(2)

console.log(value);

// Output: 0.6931471805599453``````

## log1p() Syntax

The syntax of the `log1p()` method is:

``Math.log1p(x)``

Here, `log1p()` is a static method. Hence, we need to access the method using the class name, `Math`.

## log1p() Parameters

The `log1p()` method takes in:

• x - a number

## log1p() Return Values

The `log1p()` method returns:

• natural logarithm (base e) of (1+ given number).
• `NaN` for negative numbers and non-numeric arguments.

## Example 1: JavaScript Math.log1p()

``````// find the base e log value of 1 + 1
var value1 = Math.log1p(1);

console.log(value1);

// find the base e log value of 1 + 8
var value2=Math.log1p(8);

console.log(value2)

// find the base 2 log value of 1 + 5
var value3 = Math.log1p(5);

console.log(value3); ``````

Output

```0.6931471805599453
2.1972245773362196
1.791759469228055```

In the above example,

• `Math.log1p(1)` - computes the base e log value of 1 + 1
• `Math.log1p(8)` - computes the base e log value of 1 + 8
• `Math.log1p(5)` - computes the base e log value of 1 + 5

## Example 2: log1p() With 0

``````
// find the base e log value of 1 + 0
var value = Math.log1p(0);

console.log(value);

// Output:  0``````

In the above example, we have used the `log1p()` method to compute the base e log value of 1 + 0.

The output `0` represents that the base e log value of 1 + 0 is 0.

## Example 3: log1p() With Negative Values

``````// find the base e log value of -1
var value = Math.log(-1);

console.log(value);

// Output:  NaN``````

In the above example, we have used the `log()` method to compute the base e log value of a negative number.

The output `NaN` stands for Not a Number. We get this result because the base e log value of negative numbers is undefined.