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# Math.Tan Method

Visual Studio 2008

Returns the tangent of the specified angle.

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

## Syntax

```'Declaration
Public Shared Function Tan ( _
a As Double _
) As Double
'Usage
Dim a As Double
Dim returnValue As Double

returnValue = Math.Tan(a)
```

#### Parameters

a
Type: System.Double

An angle, measured in radians.

#### Return Value

Type: System.Double
The tangent of a. If a is equal to NaN, NegativeInfinity, or PositiveInfinity, this method returns NaN.

## Remarks

The angle, a, must be in radians. Multiply by Math.PI/180 to convert degrees to radians.

## Examples

The following example demonstrates how to calculate the tangent of an angle and display it to the console.

```' This example demonstrates Math.Atan()
'                           Math.Atan2()
'                           Math.Tan()
Imports System

Class Sample
Public Shared Sub Main()
Dim x As Double = 1.0
Dim y As Double = 2.0
Dim angle As Double
Dim radians As Double
Dim result As Double

' Calculate the tangent of 30 degrees.
angle = 30
radians = angle *(Math.PI / 180)
result = Math.Tan(radians)
Console.WriteLine("The tangent of 30 degrees is {0}.", result)

' Calculate the arctangent of the previous tangent.
radians = Math.Atan(result)
angle = radians *(180 / Math.PI)
Console.WriteLine("The previous tangent is equivalent to {0} degrees.", angle)

' Calculate the arctangent of an angle.
Dim line1 As [String] = "{0}The arctangent of the angle formed by the x-axis and "
Dim line2 As [String] = "a vector to point ({0},{1}) is {2}, "
Dim line3 As [String] = "which is equivalent to {0} degrees."

radians = Math.Atan2(y, x)
angle = radians *(180 / Math.PI)

Console.WriteLine(line1, Environment.NewLine)
Console.WriteLine(line2, x, y, radians)
Console.WriteLine(line3, angle)
End Sub 'Main
End Class 'Sample
'
'This example produces the following results:
'
'The tangent of 30 degrees is 0.577350269189626.
'The previous tangent is equivalent to 30 degrees.
'
'The arctangent of the angle formed by the x-axis and
'a vector to point (1,2) is 1.10714871779409,
'which is equivalent to 63.434948822922 degrees.
'
```

## Platforms

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.

## Version Information

#### .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

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