Parameters

y

Type: SystemDouble
The y coordinate of a point.

x

Type: SystemDouble
The x coordinate of a point.

Return Value

Type: 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.