Acos Method

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Returns the angle whose cosine is the specified number.

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

static double Acos(
	double d


Type: System..::..Double
A number representing a cosine, where d must be greater than or equal to -1, but less than or equal to 1.

Return Value

Type: System..::..Double
An angle, θ, measured in radians, such that 0 θ π
NaN if d < -1 or d > 1 or d equals NaN.

Multiply the return value by 180/Math..::..PI to convert from radians to degrees.