C# has a built-in **`Math` class** that provides useful mathematical functions and operations. The class has the `Log()` function, which is used to compute the log of a specific number.

## Parameter
- **`value`**: It is of the `Double` type and represents the input value that is determined by finding `Log()`. Its range is all double numbers.


## Return value

- **`Double`**: It returns a `Double` number representing the natural log of the `value`. 
- **`NaN`**: It returns this for _negative_ or `NaN` input in `value`.
- **`PositiveInfinity`**: It returns this if `value` is `PositiveInfinity`.

- **`NegativeInfinity`**: It returns this if `value` is `0`.



> The **natural log** is the log to the base `e`, which is a mathematical expression with value 2.71828.

public static double Log (double value, double newbase);

## Parameter

- **`value`**: It is one of the `Double` type and represents the input value, which is determined by finding `Log()`. Its range is all double numbers.
- **`newbase`**: It is of the `Double` type and represents the new base value for `Log()`. Its range is all double numbers.

## Return value

- **`Double`**: It returns a `Double` number representing the log to the base `newbase` of the `value`. 
- **`NaN`**: It returns this if:
 
  - `value` < 0; `newbase` = any
  - `value` = any;	`newbase` < 0
  - `value` != 1; `newbase` = 0
  - `value` != 1; `newbase` = +∞
  - `value` = NaN; `newbase` = any
  - `value` = any;	`newbase` = NaN
  - `value` = any; `newbase` = 1 

- **`PositiveInfinity`**: It returns this if:
   
  - `value` = 0; 0 < `newbase` < 1
  - `value` = + ∞; `newbase` > 1
 
- **`NegativeInfinity`**: It returns this if:

  - `value` = 0; `newbase` > 1
  - `value` = +∞; 0 < `newbase` < 1

using System;
class Educative
{
    static void Main()
    {
        Double result = Math.Log(1.2);
        System.Console.WriteLine("Log(1.2) = "+ result);

        Double result1 = Math.Log(9.9, 0.1);
        System.Console.WriteLine("Log(9.9, 0.1) = "+ result1);
    }
}

What is Math.Log() in C#?

Natural log

Syntax

Parameter

Return value

Log to a base

Syntax

Parameter

Return value

Example