Example: PHP Program to Find Roots of Quadratic Equation using sqrt() Function

<?php
// PHP Program to Find Roots of Quadratic Equation using sqrt() Function

$p = 7.7;
$q = 6.6;
$r = 5.5;
$r1 = $r2 = $rp = $ip = 0;

// $p, $q, and $r - To store the real numbers
// $d  - To store the discriminant
// $r1 - To store the first root
// $r2 - To store the second root
// $rp - To store the real part
// $ip - To store the image part

echo "----These are the values of the coefficients----\n";
echo $p, "\n", $q, "\n", $r, "\n";

$d = $q * $q - 4 * $p * $r;

// This is the condition for real and different roots
if ($d > 0) {
    $r1 = (-$q + sqrt($d)) / (2 * $p);
    $r2 = (-$q - sqrt($d)) / (2 * $p);
    echo "\n\nThe r1 = ", $r1, " & r2 = ", $r2, "\n";
}

// This is the condition for real and equal roots
else if ($d == 0) {
    $r1 = $r2 = -$q / (2 * $p);
    echo "\n\nThe r1 = r2 = ", $r1, ";\n";
}

// if the roots are not real number
else {
    $rp = -$q / (2 * $p);
    $ip = sqrt(-$d) / (2 * $p);
    echo "\n\nThe r1 = ", number_format($rp, 2), "+", number_format($ip, 2), "i & r2 = ", number_format($rp, 2), "-", number_format($ip, 2), "i\n";
}
    
?>