sqrt.go https://tour.golang.org/flowcontrol/8

sqrt.go

// Square root implementation using Newton's Method

package main

import (
	"fmt"
	"math"
)

func Sqrt(x float64) (z float64) {
	z = x
	_z := z

	for {
		z -= (z*z-x)/(2*z)
		if math.Abs(_z-z) == 0 { break }
		_z = z;
	}
	return
}

func main() {
	fmt.Printf("\n%v\n%v", Sqrt(500), math.Sqrt(500))
}