JavaScript Math log1p()

In this tutorial, you will learn about the JavaScript Math.log1p() method with the help of examples.

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.


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