math类

package com.API;

import java.util.Scanner;

//Math数学类
public class TestMath {
    public static void main(String[] args) {
        //JDK看API文档 https://docs.oracle.com/javase/8/docs/api/
//        System.out.println(Math.abs(-12));//abs获取绝对值
//        System.out.println(Math.abs(12));
//        System.out.println(Math.max(10,15));
//        //pow 幂
//        System.out.println(Math.pow(3,3));
//        //round  四舍五入
//        System.out.println(Math.round(4.5));
//        //sqrt 求平方根
//        System.out.println(Math.sqrt(9));
//        //
        System.out.println("请计算一元二次方程的根");
        Scanner s1 = new Scanner(System.in);
        while (true) {
            System.out.println("请输入a");
            double a = s1.nextInt();
            System.out.println("请输入b");
            double b = s1.nextInt();
            System.out.println("请输入c");
            double c = s1.nextInt();
            double dt = Math.pow(b,2) - 4 * a * c;
            if (dt < 0){
                System.out.println("无解");
            }else if (dt == 0){
                System.out.println("次方程只有一个解");
                double x = -b / (2*a);
                System.out.println("x=" + x);
            }else {
                System.out.println("此方程有两个解");
                double x1 = (-b + Math.sqrt(dt)) / (2*a);
                double x2 = (-b - Math.sqrt(dt)) / (2*a);
                System.out.println("x1的解为=" + x1 + " " + "x2的解为=" + x2);
            }
        }


    }
}

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