JavaScript Math log()

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

The Math.log() method returns the natural logarithm of a number. It is equivalent to ln(x) in mathematics.

Example

// calculate the log base e of 1 var value = Math.log(1);
console.log(value); // Output: 0

log() Syntax

The syntax of log() is:

Math.log(x)

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


log() Parameter

The log() method takes in:

  • x - a number

log() Return Values

The log() method returns:

  • the base e logarithm of the given number.
  • NaN for negative numbers and non-numeric arguments.

Example 1: JavaScript Math.log()

// find the base e log value of 1 var value1 = Math.log(1);
console.log(value1);
// find the base e log value of 10 var value2=Math.log(10);
console.log(value2)
// find the base e log value of 8 var value3 = Math.log(8);
console.log(value3);

Output

0
2.302585092994046
2.0794415416798357

In the above example,

  • Math.log(1) - computes the base e log value of 1
  • Math.log(10) - computes the base e log value of 10
  • Math.log(8) - computes the base e log value of 8

Example 2: log() With 0

// find the base e log value of 0 var value = Math.log(0);
console.log(value); // Output: -Infinity

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

The output -Infinity indicates that the base e log value of 0 is negative infinity.


Example 3: log() 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 the negative number -1.

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


Example 4: log() With Euler's Constant e

// log() with Euler's constant e var value = Math.log(Math.E);
console.log(value); // Output: 1

In the above example, we have used the log() method to compute the base e log value of Math.E (Euler's constant e).

The output 1 indicates that the base e log value of e is 1 i.e. ln(e) = 1.


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