go Expm1()
Expm1()方法语法
func Expm1(x float64) float64
go源码对Expm1()方法的介绍：
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.golang标准库模块math.Expm1()方法，返回值为e的x次方，并减去1，即e**x - 1。当参数x接近于0时，比Exp(x)-1更精确。除此之外，Expm1(+Inf) = +Inf；Expm1(-Inf) = -1；Expm1(NaN) = NaN。
math.Expm1()方法实例代码
func main() {
expm1_v := math.Expm1(1)
fmt.Println(expm1_v)
fmt.Println(math.E - 1)
}运行go文件，得到输出：
1.718281828459045
1.7182818284590453