题目描述

代码如下

二分

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double x = sc.nextDouble();
        double l = -10000;
        double r = 10000;
        while(r - l > 1e-8) {//精度比所求精度高 2位
            double mid = (l + r)/2;
            if(mid * mid * mid >= x) r = mid;
            else l = mid;
        }
        //System.out.println(String.format("%.6f", l));
        System.out.printf("%.6f", l); //保留 6位小数
    }
}

幂次

需要注意的是：

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double f = sc.nextDouble();

        if(f < 0) {
            f = Math.abs(f);
            System.out.printf("-%.6f", Math.pow(f, 1.0/3));
        }else {
            System.out.printf("%.6f", Math.pow(f, 1.0/3));
        }
    }
}

开立方

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double f = sc.nextDouble();
        System.out.printf("%.6f", Math.cbrt(f));
    }
}