nth root implementation

Question

I am working on a way to calculate the n^th root of a number. However, I am having problems with the n^th root of negative numbers.

Most people s

Answer 1

I use the method below. Maybe it's not the most accurate, but it works well in my case.

public double root(double num, double root) {
    double d = Math.pow(num, 1.0 / root);
    long rounded = Math.round(d);
    return Math.abs(rounded - d) < 0.00000000000001 ? rounded : d;
}

Answer 2

    public double root(double num, double root) {
        double y=1;
        double x;
        while(Math.pow(x, root) != num) {
            if(Math.pow(x, root) > num) {
                x=x-y;
                y=y/10;
            } else {
                x=x+y;
            }
        }
        return x;
    }   

This should work fine for you, although it isn't compact it uses as little math functions as possible.