Advanced Exercise: Complex cube roots http://tour.golang.org/#48

complexpower.go

package main

import (
    "fmt"
    "math/cmplx"
)

func Cbrt(x complex128) complex128 {
    z := complex128(1)
    for i := 0; i < 10; i++ {
    	z = z - (z*z*z - x)/(3 * z *z)
    }
    return z
}

func main() {
    fmt.Println(Cbrt(2 + 3i), cmplx.Pow(2.0 + 3i, 1.0/3))
}