Math.Atan2 メソッド

.NET Framework クラス ライブラリ リファレンス

Math.Atan2 メソッド

タンジェントが 2 つの指定された数の商である角度を返します。

名前空間: System
アセンブリ: mscorlib (mscorlib.dll 内)
構文

Visual Basic (宣言)

Public Shared Function Atan2
 ( _
    y As Double, _
    x As Double _
) As Double

Visual Basic (使用法)

Dim y As Double
Dim x As Double
Dim returnValue As Double

returnValue = Math.Atan2(y, x)

C#

public static double Atan2 (
    double y,
    double x
)

C++

public:
static double Atan2 (
    double y, 
    double x
)

J#

public static double Atan2 (
    double y, 
    double x
)

JScript

public static function Atan2
 (
    y : double, 
    x : double
) : double

パラメータ

y

点の y 座標。

x

点の x 座標。

戻り値
π ≤ θ ≤ π および tan(θ) = y / x のラジアンで示した角度 θ。(x, y) は、デカルト座標の点を示します。次の点に注意してください。

• クワドラント 1 の (x, y) の場合は、0 < θ < π/2。

• クワドラント 2 の (x, y) の場合は、π/2 < θ≤π。

• クワドラント 3 の (x, y) の場合は、-π < θ < -π/2。

• クワドラント 4 の (x, y) の場合は、-π/2 < θ < 0。

解説

戻り値は、デカルト座標の x 軸と、原点 (0,0) から始まり点 (x,y) で終了するベクタによって構成される角度です。

使用例

Visual Basic

' 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.
'

C#

// This example demonstrates Math.Atan()
//                           Math.Atan2()
//                           Math.Tan()
using System;

class Sample 
{
    public static void Main()
 
    {
    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);
    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.
    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);

    Console.WriteLine(line1, Environment.NewLine);
    Console.WriteLine(line2, x, y, radians);
    Console.WriteLine(line3, angle);
    }
}
/*
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.
*/

C++

// This example demonstrates Math.Atan()
//                           Math.Atan2()
//                           Math.Tan()
using namespace System;
int main()
{
   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 );
   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.
   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);
   Console::WriteLine( line1, Environment::NewLine );
   Console::WriteLine( line2, x, y, radians );
   Console::WriteLine( line3, angle );
}

/*
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.
*/

J#

// This example demonstrates Math.Atan()
//                           Math.Atan2()
//                           Math.Tan()

import System.*;

class Sample
{
    public static void main(String[]
 args)
    {
        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 = System.Math.Tan(radians);
        Console.WriteLine("The tangent of 30 degrees is {0}.", 
            System.Convert.ToString(result));

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

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

        Console.WriteLine(line1, Environment.get_NewLine());
        Console.WriteLine(line2, System.Convert.ToString(x), 
            System.Convert.ToString(y), System.Convert.ToString(radians));
        Console.WriteLine(line3, System.Convert.ToString(angle));
    } //main
} //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.
*/

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0、1.0

参照

関連項目
Math クラス
Math メンバ
System 名前空間