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Atan2 Method

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

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

Syntax

'Declaration
Public Shared Function Atan2 ( _
    y As Double, _
    x As Double _
) As Double
public static double Atan2(
    double y,
    double x
)
public:
static double Atan2(
    double y, 
    double x
)
static member Atan2 : 
        y:float * 
        x:float -> float 
public static function Atan2(
    y : double, 
    x : double
) : double

Parameters

Return Value

Type: System. . :: . .Double
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 the following:

  • For (x, y) in quadrant 1, 0 < θ < π/2.

  • For (x, y) in quadrant 2, π/2 < θ≤π.

  • For (x, y) in quadrant 3, -π < θ < -π/2.

  • For (x, y) in quadrant 4, -π/2 < θ < 0.

For points on the boundaries of the quadrants, the return value is the following:

  • If y is 0 and x is not negative, θ = 0.

  • If y is 0 and x is negative, θ = π.

  • If y is positive and x is 0, θ = π/2.

  • If y is negative and x is 0, θ = -π/2.

If x or y is NaN, or if x and y are either PositiveInfinity or NegativeInfinity, the method returns NaN.

Remarks

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).

.NET Framework Security

See Also

Reference

Math Class

System Namespace