Math.Atan Method
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Returns the angle whose tangent is the specified number.
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
<SecuritySafeCriticalAttribute> _
Public Shared Function Atan ( _
d As Double _
) As Double
[SecuritySafeCriticalAttribute]
public static double Atan(
double d
)
Parameters
- d
Type: System.Double
A number representing a tangent.
Return Value
Type: System.Double
An angle, θ, measured in radians, such that -π/2 ≤θ≤π/2.
-or-
NaN if d equals NaN, -π/2 rounded to double precision (-1.5707963267949) if d equals NegativeInfinity, or π/2 rounded to double precision (1.5707963267949) if d equals PositiveInfinity.
Remarks
A positive return value represents a counterclockwise angle from the x-axis; a negative return value represents a clockwise angle.
Multiply the return value by 180/Math.PI to convert from radians to degrees.
Examples
The following example demonstrates how to calculate the arctangent of a value and display it to the console.
' This example demonstrates Math.Atan()
' Math.Atan2()
' Math.Tan()
Class Example
Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
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)
outputBlock.Text &= String.Format("The tangent of 30 degrees is {0}.", result) & vbCrLf
' Calculate the arctangent of the previous tangent.
radians = Math.Atan(result)
angle = radians * (180 / Math.PI)
outputBlock.Text &= String.Format("The previous tangent is equivalent to {0} degrees.", angle) & vbCrLf
' 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)
outputBlock.Text &= String.Format(line1, vbCrLf) & vbCrLf
outputBlock.Text &= String.Format(line2, x, y, radians) & vbCrLf
outputBlock.Text &= String.Format(line3, angle) & vbCrLf
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.
'
// This example demonstrates Math.Atan()
// Math.Atan2()
// Math.Tan()
using System;
class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
double x = 1.0;
double y = 2.0;
double angle;
double radians;
double result;
// Calculate the tangent of 30 degrees.
angle = 30;
radians = angle * (Math.PI / 180);
result = Math.Tan(radians);
outputBlock.Text += String.Format("The tangent of 30 degrees is {0}.", result) + "\n";
// Calculate the arctangent of the previous tangent.
radians = Math.Atan(result);
angle = radians * (180 / Math.PI);
outputBlock.Text += String.Format("The previous tangent is equivalent to {0} degrees.", angle) + "\n";
// Calculate the arctangent of an angle.
String line1 = "{0}The arctangent of the angle formed by the x-axis and ";
String line2 = "a vector to point ({0},{1}) is {2}, ";
String line3 = "which is equivalent to {0} degrees.";
radians = Math.Atan2(y, x);
angle = radians * (180 / Math.PI);
outputBlock.Text += String.Format(line1, "\n") + "\n";
outputBlock.Text += String.Format(line2, x, y, radians) + "\n";
outputBlock.Text += String.Format(line3, angle) + "\n";
}
}
/*
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.
*/
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.