Math.Atan2(Double, Double) Method

定義

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。 Returns the angle whose tangent is the quotient of two specified numbers.

public static double Atan2 (double y, double x);
パラメーター
y
Double

点の y 座標。 The y coordinate of a point.

x
Double

点の x 座標。 The x coordinate of a point.

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。 An angle, θ, measured in radians, such that -π≤θ≤π, and tan(θ) = y / x, where (x, y) is a point in the Cartesian plane. 次の点に注意してください。 Observe the following: - クワドラント 1 の (x, y) の場合は、0 < θ < π/2。 - For (x, y) in quadrant 1, 0 < θ < π/2. - クワドラント 2 の (x, y) の場合は、π/2 < θ≤π。 - For (x, y) in quadrant 2, π/2 < θ≤π. - クワドラント 3 の (x, y) の場合は、-π < θ < -π/2。 - For (x, y) in quadrant 3, -π < θ < -π/2. - クワドラント 4 の (x, y) の場合は、-π/2 < θ < 0。 - For (x, y) in quadrant 4, -π/2 < θ < 0. クワドラント間の境界上にある点の場合は、次の戻り値になります。 For points on the boundaries of the quadrants, the return value is the following: - y が 0 で x が負数でない場合は、θ = 0。 - If y is 0 and x is not negative, θ = 0. - y が 0 で x が負の場合は、θ = π。 - If y is 0 and x is negative, θ = π. - y が正で x が 0 の場合は、θ = π/2。 - If y is positive and x is 0, θ = π/2. - y が負数で x が 0 の場合は、θ = -π/2。 - If y is negative and x is 0, θ = -π/2. - y が 0 かつ x が 0 の場合は、θ = 0。 - If y is 0 and x is 0, θ = 0. x または yNaN であるか、x または yPositiveInfinity または NegativeInfinity のいずれである場合、メソッドは NaN を返します。 If x or y is NaN, or if x and y are either PositiveInfinity or NegativeInfinity, the method returns NaN.

次の例では、角度とベクトルのアーク タンジェントを計算する方法を示します。The following example demonstrates how to calculate the arctangent of an angle and a vector. 結果の値は、コンソールに表示されます。The resulting value is displayed in the console.

// 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.
*/
// 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.
*/
' 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.
'

注釈

戻り値は、x 軸、およびベクトルは原点 (0, 0) から開始し、ポイント、(x, y) で終了して形成されたデカルト角度です。The return value is the angle in the Cartesian plane formed by the x-axis, and a vector starting from the origin, (0,0), and terminating at the point, (x,y).

適用対象