golang：为什么我得到+ Inf而不是整数或浮点数？

我正在学习golang，致力于计算金钱的时间价值 我试图计算一段时间来说，加倍你的钱。我正在使用的公式是period = log(fv/pv) / log(1 + i)。我到目前为止是...

package main
import (
    "fmt"
    "math"
)
var (
    interest,
    futureValue,
    period,
    presentValue float64
)
var rate float64 = interest / 100 //converts interest into decimal... interest / 100
var ratex float64 = 1 + interest //used for (1 + i)
func main() {
    numPeriod()
}
func numPeriod() {
    fmt.Println("Enter interest amount: ")
    fmt.Scanf("%g", &interest)
    fmt.Println("Enter present value: ")
    fmt.Scanf("%g", &presentValue)
    fmt.Println("Enter future value: ")
    fmt.Scanf("%g", &futureValue)
    var logfvpvFactor float64 = futureValue / presentValue
    var logi float64 = math.Log(ratex)
    var logfvpv float64 = math.Log(logfvpvFactor)
    period = logfvpv / logi
    fmt.Printf("Number of period/s is = %g\n", period)
}

运行这个，我得到...

Number of period/s is = +Inf

...我正在寻找的答案是一个整数或一个浮点数。我如何获得？ 谢谢你的帮助！