# Ruby - Math.log() Method

The Ruby Math.log() method returns the natural logarithm (base e) or logarithm to the specified base of a given number.

### Syntax

```Math.log(x, base)
```

### Parameters

 `x` `Required. ` Specify the number. `base` `Optional. ` Specify the base. Default is e.

### Return Value

Returns the natural logarithm or logarithm to the specified base of a given number.
If the x or base is negative, DomainError is thrown.
If the x is 0, it returns -Infinity.

### Example:

In the example below, Math.log() method is used to calculate the natural logarithm of a given number.

```puts "Math.log(1) = #{Math.log(1)}"
puts "Math.log(Math::E) = #{Math.log(Math::E)}"
puts "Math.log(10) = #{Math.log(10)}"
puts "Math.log(0) = #{Math.log(0)}"
```

The output of the above code will be:

```Math.log(1) = 0.0
Math.log(Math::E) = 1.0
Math.log(10) = 2.302585092994046
Math.log(0) = -Infinity
```

### Example:

In this example, Math.log() method is used to calculate the specified base logarithm of a given number.

```puts "Math.log(2, 2) = #{Math.log(2, 2)}"
puts "Math.log(81, 3) = #{Math.log(81, 3)}"
puts "Math.log(100, 10) = #{Math.log(100, 10)}"
```

The output of the above code will be:

```Math.log(2, 2) = 1.0
Math.log(81, 3) = 4.0
Math.log(100, 10) = 2.0
```

❮ Ruby Math Module

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