Question

Java Programming

Question 4 (10 points):

Solutions for a quadratic equation ax(squared)+bx+c= 0. where a does not equal zero are as follows.

r1=( −b+√b(squared)−4ac)/2a

r2=(−b−√b(squared)−4ac)/2a

if b(squared)−4ac <0, equation doesn’t have real roots. If it is 0 there is one

root(r1=r2). Write a Java program to read a,b and c from keyboard and find the roots, if they exist.

Note:

You need to have a method that takes 3 real values as arguments

Answer 1

Program:-

import java.util.*;
import java.lang.*;
class root
{
   void calculate(int a,int b,int c) //method with 3 arguments a,b,c and checks whether they are real or imaginary(no roots)
   {
       if(b*b-4*a*c<0) //condition to check whether roots exists
       {
           System.out.println("The equation does not have roots");
       }
       if(b*b-4*a*c==0) //this condition verifies that roots are equal
       {
           System.out.println("There is one that is r1=r2");  
       }
   }
   public static void main(String[] args) //main methos
   {
       int a,b,c; //declaring variables a,b,c
       double r1,r2;
       Scanner scan=new Scanner(System.in); //Scanner method to take input from variables
       System.out.println("enter a");
       a=scan.nextInt(); // keyboard input for a
       System.out.println("enter b");
       b=scan.nextInt();  // keyboard input for b
       System.out.println("enter c");
       c=scan.nextInt();  // keyboard input for c
       root x=new root(); //instance for class root
       x.calculate(a,b,c); //calling method calculate
       r1=(-b+(Math.sqrt(b*b-4*a*c)))/(2*a); //calculating r1
       r2=(-b-(Math.sqrt(b*b-4*a*c)))/(2*a); // calculating r2
       System.out.println("r1="+r1+" r2="+r2); // printing r1,r2 values
   }
}

Output:-

The output contains the results for inputs a=1,b=2,c=1

and

It contains the results when inputs are a=4,b=1,c=1

$C: \Users shashank \OneDrive \Desktop practice javac root.java C: \Users shashank \OneDrive \Desktop practice java root enter a enter b enter o There is one that is r1-r2 r1--1.0 r2--1.0 C: \Users shashank \OneDrive \Desktoplpractice java root enter a 4 enter b enter c The equation does not have roots r1-NaN r2-NaN$