Square negative number in go

Question

I'm having problems to square a negative number in go...

(2*(1-0.5)-4)/((4*(4-2))/(2-1))^(1/2) = -1.06066017

but with go I get NaN

package main
import (
    "fmt"
    "math"
)

func main() {
    fmt.Print(math.Sqrt((2*(1-0.5) - 4) / ((4 * (4 - 2)) / (2 - 1))))
}

or if I use math.Abs like this:

fmt.Print(math.Sqrt(math.Abs((2*(1-0.5) - 4) / ((4 * (4 - 2)) / (2 - 1)))))

I got back: 0.6123724356957 that is not correct, the correct result is: -1.06066017

is there any way to work around this?

Answer 1

The problem is:

(2*(1-0.5)-4)/((4*(4-2))/(2-1))^(1/2)

is evaluated as (2*(1-0.5)-4) divided by ((4*(4-2))/(2-1))^(1/2) in your calculator, which indeed yields -1.06...

But you gave Go (2*(1-0.5)-4)/((4*(4-2))/(2-1)), which is a negative number, and told it to calculate the square root of that, which would be complex.

So try:

fmt.Print((2*(1-0.5) - 4) / math.Sqrt(((4 * (4 - 2)) / (2 - 1))))