typedNewtonSqrt.fs

let newtonSqrt (x : float) : float =
    let accuracy : float = 0.00001  // desired accuracy
    let rec iterate (x : float) (a : float) : float =
        let diff : float = x - a*a
        if abs diff <= accuracy
            then a
            else iterate x ((a + x/a) / 2.0)
    iterate x (x/2.0)