go/src/math/expm1.go

// Expm1 returns e**x - 1, the base-e exponential of x minus 1.
// It is more accurate than [Exp](x) - 1 when x is near zero.
//
// Special cases are:
//
//	Expm1(+Inf) = +Inf
//	Expm1(-Inf) = -1
//	Expm1(NaN) = NaN
//
// Very large values overflow to -1 or +Inf.
func Expm1(x float64) float64 { … }

func expm1(x float64) float64 { … }