Write the following Java methods • boolean real-sols(double a, double b, double

Question

Write the following Java methods • boolean real-sols(double a, double b, double c): it returns true if the 2nd degree equation ax2 + bx + c has real solutions • double solution1(double a, double b, double c): If the equation ax2 + bx + c has real solutions it return the smallest of the two. If it doesn’t have real solutions it should return the value 0 and an error message. • double solution2(double a, double b, double c): If the equation ax2 + bx + c has real solutions it return the biggest of the two. If it doesn’t have real solutions it should return the value 0 and an error message. • Test your methods within a class and check that they work properly. Use the method real-sols(double a, double b, double c) in the implementation of the other 2 methods.

Explanation / Answer

Quad.java

import java.util.Scanner;

public class Quad {

   public static void main(String[] args) {

        System.out.println ("Please enter a value for a");
       Scanner sc = new Scanner(System.in);
       double a = sc.nextDouble();
       System.out.println(a);

       System.out.println ("Please enter a value for b");
       double b = sc.nextDouble();
       System.out.println(b);

       System.out.println ("Please enter a value for c");
       double c = sc.nextDouble();
       System.out.println(c);

       double e = solution1(a,b,c);
       System.out.println ("smallest value = "+e);
       double f= solution2(a,b,c);
       System.out.println ("biggest value = "+f);

   }

   public static double solution1(double a, double b, double c)
   {

           boolean d = real_sols(a,b,c);
       System.out.println (d);
       double x = 0;
       x = (-b + (Math.sqrt((b*b - ((4 * a * c))))))/ (2 * a);

       double y = 0;
       y = (-b - (Math.sqrt((b*b - ((4*a*c))))))/ (2 * a);

       if (((b*b - ((4 * a * c))) < 0) == true) {
       System.out.println ("There are no real roots");
       }
       if (((b*b - ((4 * a * c))) < 0) == false)
       {}if(x>y){
           return y;   }
       else
       {   return x;}

}
   public static double solution2(double a, double b, double c)
   {

       double x = 0;
       x = (-b + (Math.sqrt((b*b - ((4 * a * c))))))/ (2 * a);

       double y = 0;
       y = (-b - (Math.sqrt((b*b - ((4*a*c))))))/ (2 * a);

               boolean d = real_sols(a,b,c);
       System.out.println (d);
       if (((b*b - ((4 * a * c))) < 0) == true) {
       System.out.println ("There are no real roots");
       }
       if (((b*b - ((4 * a * c))) < 0) == false)
       {}
               if(x>y){
           return x;
               }
           else
           {return y;}

}
public static boolean real_sols(double a, double b, double c)
{

       if (((b*b - ((4 * a * c))) < 0) == true)
       {
           return false;
       }
       return true;

   }
   }

Output :

Please enter a value for a
2
2.0
Please enter a value for b
8
8.0
Please enter a value for c
2
2.0
true
smallest value = -3.732050807568877
true
biggest value = -0.2679491924311228

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