## C# Math.Log() – Examples

In this tutorial, we will learn about the C# Math.Log() method, and learn how to use this method to the natural logarithm of a number or logarithm of a number in specified base, with the help of examples.

## Log(Double d)

Math.Log(d) returns the natural (base e) logarithm of a specified number `d`.

### Syntax

The syntax of Log() method is

`Math.Log(Double d)`

where

Return Value

The method returns a value of type double.

### Example 1 – Log(d)

In this example, we will find the natural logarithm of the following values.

• Positive Value
• Negative Value
• Positive Infinity
• Negative Infinity
• Zero

C# Program

```using System;

class Example {
static void Main(string[] args) {
Double d, result;

d = 8;
result = Math.Log(d);
Console.WriteLine(\$"Log({d}) = {result}");

d = -7;
result = Math.Log(d);
Console.WriteLine(\$"Log({d}) = {result}");

d = Double.PositiveInfinity;
result = Math.Log(d);
Console.WriteLine(\$"Log({d}) = {result}");

d = Double.NegativeInfinity;
result = Math.Log(d);
Console.WriteLine(\$"Log({d}) = {result}");

d = 0;
result = Math.Log(d);
Console.WriteLine(\$"Log({d}) = {result}");
}
}```

Output

```Log(8) = 2.07944154167984
Log(-7) = NaN
Log(∞) = ∞
Log(-∞) = NaN
Log(0) = -∞```

## Log(Double d, Double newBase)

Math.Log(d, newBase) returns the logarithm of a specified number `d` in a specified base `newBase`.

### Syntax

The syntax of Log() method is

`Math.Log(Double a, Double newBase)`

where

Return Value

The method returns a value of type double.

### Example 2 – Log(d, newBase)

In this example, we will find the logarithm of the following values.

• Positive Value to Base 3
• Negative Value to Base 3
• 3 to the Base 3
• Negative Infinity to Base 3
• Zero to Base 3

C# Program

```using System;

class Example {
static void Main(string[] args) {
Double d, newBase, result;

d = 9;
newBase = 3;
result = Math.Log(d, newBase);
Console.WriteLine(\$"Log({d}) to the base {newBase} = {result}");

d = -7;
newBase = 3;
result = Math.Log(d, newBase);
Console.WriteLine(\$"Log({d}) to the base {newBase} = {result}");

d = 3;
newBase = 3;
result = Math.Log(d, newBase);
Console.WriteLine(\$"Log({d}) to the base {newBase} = {result}");

d = Double.NegativeInfinity;
newBase = 3;
result = Math.Log(d, newBase);
Console.WriteLine(\$"Log({d}) to the base {newBase} = {result}");

d = 0;
newBase = 3;
result = Math.Log(d, newBase);
Console.WriteLine(\$"Log({d}) to the base {newBase} = {result}");
}
}```

Output

```Log(9) to the base 3 = 2
Log(-7) to the base 3 = NaN
Log(3) to the base 3 = 1
Log(-∞) to the base 3 = NaN
Log(0) to the base 3 = -∞```

### Conclusion

In this C# Tutorial, we have learnt the syntax of C# Math.Log() method, and also learnt how to use this method with the help of examples.