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Math.Log10 Method

Updated: August 2008

Returns the base 10 logarithm of a specified number.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

'Declaration
Public Shared Function Log10 ( _
	d As Double _
) As Double
'Usage
Dim d As Double 
Dim returnValue As Double 

returnValue = Math.Log10(d)

Parameters

d
Type: System.Double

A number whose logarithm is to be found.

Return Value

Type: System.Double

Sign of d

Returns

Positive

The base 10 log of d; that is, log 10 d.

Zero

NegativeInfinity

Negative

NaN

If d is equal to NaN, this method returns NaN. If d is equal to PositiveInfinity, this method returns PositiveInfinity.

Parameter d is specified as a base 10 number.

The following example uses Log10 to return the base 10 logarithm of selected values.

Module Example
   Public Sub Main()
      Dim numbers() As Double = {-1, 0, .105, .5, .798, 1, 4, 6.9, 10, 50, _
                                 100, 500, 1000, Double.MaxValue}

      For Each number As Double In numbers
         Console.WriteLine("The base 10 log of {0} is {1}.", _
                           number, Math.Log10(number))
      Next 
   End Sub 
End Module 
' The example displays the following output: 
'       The base 10 log of -1 is NaN. 
'       The base 10 log of 0 is -Infinity. 
'       The base 10 log of 0.105 is -0.978810700930062. 
'       The base 10 log of 0.5 is -0.301029995663981. 
'       The base 10 log of 0.798 is -0.0979971086492706. 
'       The base 10 log of 1 is 0. 
'       The base 10 log of 4 is 0.602059991327962. 
'       The base 10 log of 6.9 is 0.838849090737255. 
'       The base 10 log of 10 is 1. 
'       The base 10 log of 50 is 1.69897000433602. 
'       The base 10 log of 100 is 2. 
'       The base 10 log of 500 is 2.69897000433602. 
'       The base 10 log of 1000 is 3. 
'       The base 10 log of 1.79769313486232E+308 is 308.254715559917.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

August 2008

Replaced the example.

Customer feedback.

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