Question

Solve Quadratic Equation IN JAVA (static methods, parameters, arguments, Math functions)

Write a program that will print the real-valued solutions of a quadratic equation

ax^2+bx+c=0

For example:

Enter coefficient a:  1
Enter coefficient b:  10
Enter coefficient c:  2
The solutions are -0.2041684766872809, and -9.79583152331272

For another example:

Enter coefficient a:  1
Enter coefficient b:  2
Enter coefficient c:  3
The equation does not have real solution

The program should use the following methods.

1. getCoeff(), which takes a String message as a parameter. It will print the message and returns the user's input (a double value)
2. hasRealSolution(), which takes the three double parameters, a, b and c, and returns true if

   b^2−4ac>=0

3. solution1() and solution2(), both take the three coefficients, a, b, and c, and returns the two solutions according to

   x = −b ± (√(b^2 − 4ac)) / (2a)

4. main(), which prompts the user for the three coefficients, and call the other methods to find the solutions.

Notice that other than getCoeff() and the main() methods, methods should not interact with the user.

Answer 1

import java.util.Scanner;

public class Main {

public static double getCoeff(String msg) {

Scanner sc = new Scanner(System.in);

System.out.println(msg);

return sc.nextDouble();

}

public static boolean hasRealSolution(double a, double b, double c) {

return (b * b - 4 * a * c) >= 0;

}

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

return ((-1 * b) + (Math.sqrt(b * b - 4 * a * c))) / (2 *a);

}

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

return ((-1 * b) - (Math.sqrt(b * b - 4 * a * c))) / (2 * a);

}

public static void main(String[] args) {

double a = getCoeff("Enter coefficient a: ");

double b = getCoeff("Enter coefficient b: ");

double c = getCoeff("Enter coefficient c: ");

if (hasRealSolution(a, b, c)) {

System.out.println("The solutions are " + solution1(a, b, c) + ", and " + solution2(a, b, c));

} else {

System.out.println("The equation does not have real solution");

}

}

}