Recursive sqrt

def  SQRT(number : Double) : Double = {

    val precisionRange : Int = 1000000
    @tailrec
    def innerSQRT (num : Double, start : Double, end : Double) : Double = {
      val mid : Double = (start+end)/2;

      if (Math.abs(mid*mid - num) <= 1.0/precisionRange)
        mid;
      else
        if (mid*mid - num > 0)
          innerSQRT(num,start,mid);
        else
          innerSQRT(num,mid, end);
    } // end of innerSQRT

    var sqrt : Double = innerSQRT(number, 0, number);
    val g : Double = precisionRange * sqrt;

    val answer : Double = g.toInt / d.toDouble;

    answer
  }