go/src/math/atan.go

// xatan evaluates a series valid in the range [0, 0.66].
func xatan(x float64) float64 { … }

// satan reduces its argument (known to be positive)
// to the range [0, 0.66] and calls xatan.
func satan(x float64) float64 { … }

// Atan returns the arctangent, in radians, of x.
//
// Special cases are:
//
//	Atan(±0) = ±0
//	Atan(±Inf) = ±Pi/2
func Atan(x float64) float64 { … }

func atan(x float64) float64 { … }