Question

How to find the roots of a quadratic equation in Java

Answer 1

public class MyClass {
    static void quadratic_equation_roots(double a, double b, double c) {
        double discriminant = (b * b) - (4 * a * c);
      
        double root1, root2;
        if (discriminant > 0) {
            root1 = (-b + Math.sqrt(discriminant)) / (2 * a);
            root2 = (-b - Math.sqrt(discriminant)) / (2 * a);
            System.out.println("root1 = " + root1 + "\nroot2 = " + root2);
        }
        else if(discriminant == 0) {
            root1 = root2 = -b / (2 * a);
            System.out.println("root1 = root2 = " + root1);
        }
        else if(discriminant < 0) {
            double real = -b / (2 * a);
            double imaginary = Math.sqrt(-discriminant) / (2 * a);
            System.out.println("root1 = " + real + "+" + imaginary + "i\nroot2 = " + real + "-" + imaginary + "i");
        }
    }
    public static void main(String args[]) {
        double a = 3, b = 5, c = -9;
  
        quadratic_equation_roots(a, b, c);
        System.out.println();
  
        a = 3; b = 5; c = 7;
        quadratic_equation_roots(a, b, c);
        System.out.println();
  
        a = 2; b = 4; c = 2;
        quadratic_equation_roots(a, b, c);
    }
}


  
  
  
/*
run:
  
root1 = 1.0887604324451328
root2 = -2.7554270991117993

root1 = -0.8333333333333334+1.2801909579781012i
root2 = -0.8333333333333334-1.2801909579781012i

root1 = root2 = -1.0
  
*/

 

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