# Math.Atan2(Double, Double) Método

## Definição

Retorna o ângulo cuja tangente é o quociente de dois números especificados.Returns the angle whose tangent is the quotient of two specified numbers.

``````public:
static double Atan2(double y, double x);``````
``public static double Atan2 (double y, double x);``
``static member Atan2 : double * double -> double``
``Public Shared Function Atan2 (y As Double, x As Double) As Double``

#### Parâmetros

y
Double

A coordenada y de um ponto.The y coordinate of a point.

x
Double

A coordenada x de um ponto.The x coordinate of a point.

#### Retornos

Um ângulo, θ, medido em radianos, tal que -π ≤ θ ≤ π e tan(θ) = `y` / `x`, em que (`x`, `y`) é um ponto no plano cartesiano.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. Observe o seguinte:Observe the following: - Para (`x`, `y`) no quadrante 1, 0 < θ < π/2.- For (`x`, `y`) in quadrant 1, 0 < θ < π/2.

- Para (`x`, `y`) no quadrante 2, π/2 < θ ≤ π.- For (`x`, `y`) in quadrant 2, π/2 < θ≤π.

- Para (`x`, `y`) no quadrante 3, -π < θ < -π/2.- For (`x`, `y`) in quadrant 3, -π < θ < -π/2.

- Para (`x`, `y`) no quadrante 4, -π/2 < θ < 0.- For (`x`, `y`) in quadrant 4, -π/2 < θ < 0.

Para pontos em limites dos quadrantes, o valor retornado é o seguinte:For points on the boundaries of the quadrants, the return value is the following: - Se y for 0 e x não for negativo, θ = 0.- If y is 0 and x is not negative, θ = 0.

- Se y for 0 e x for negativo, θ = π.- If y is 0 and x is negative, θ = π.

- Se y for positivo e x for 0, θ = π/2.- If y is positive and x is 0, θ = π/2.

- Se y for negativo e x for 0, θ = - π/2.- If y is negative and x is 0, θ = -π/2.

- Se y for 0 e x for 0, θ = 0.- If y is 0 and x is 0, θ = 0.

Se `x` ou `y` for NaN, ou se `x` e `y` forem PositiveInfinity ou NegativeInfinity, o método retornará NaN.If `x` or `y` is NaN, or if `x` and `y` are either PositiveInfinity or NegativeInfinity, the method returns NaN.

## Exemplos

O exemplo a seguir demonstra como calcular o arco tangente de um ângulo e um vetor.The following example demonstrates how to calculate the arctangent of an angle and a vector. O valor resultante é exibido no console do.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 result;

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

// Calculate the arctangent of the previous tangent.
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 result;

// Calculate the tangent of 30 degrees.
angle = 30;
Console.WriteLine("The tangent of 30 degrees is {0}.", result);

// Calculate the arctangent of the previous tangent.
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.";

Console.WriteLine(line1, Environment.NewLine);
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()
Class Sample
Public Shared Sub Main()
Dim x As Double = 1.0
Dim y As Double = 2.0
Dim angle As Double
Dim result As Double

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

' Calculate the arctangent of the previous tangent.
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."

angle = radians *(180 / Math.PI)

Console.WriteLine(line1, Environment.NewLine)
Console.WriteLine(line3, angle)
End Sub
End Class
'
'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.
'
``````

## Comentários

O valor de retorno é o ângulo no plano cartesiano formado pelo eixo x e um vetor começando da origem (0, 0) e terminando no ponto, (x, y).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).