JavaScript Math.log()

// 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.

Recommended Readings:

• Math.exp()
• Math.log1p()
• Math.log10()