Question

How to find the roots of a quadratic equation in JavaScript

Answer 1

function quadratic_equation_roots(a, b, c) {
    const discriminant = (b * b) - (4 * a * c);
 
    let root1 = 0, root2 = 0;
    if (discriminant > 0) {
        root1 = (-b + Math.sqrt(discriminant)) / (2 * a);
        root2 = (-b - Math.sqrt(discriminant)) / (2 * a);
        console.log(`root1 = ${root1}\nroot2 = ${root2}`);
    }
    else if(discriminant == 0) {
        root1 = -b / (2 * a);
        console.log(`root1 = root2 = ${root1}`);
    }
    else if(discriminant < 0) {
        const real = -b / (2 * a);
        const imaginary = Math.sqrt(-discriminant) / (2 * a);
        console.log(`root1 = ${real}+${imaginary}i\nroot2 = ${real}-${imaginary}i`);
    }
}
 
    
let a = 3, b = 5, c = -9;
 
quadratic_equation_roots(a, b, c);
console.log();
 
a = 3; b = 5; c = 7;
quadratic_equation_roots(a, b, c);
console.log();
 
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"
 
*/

 

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