public static function solveQuadraticEquation($a, $b, $c)
{
if ($b == 0 && $c <= 0) {
$c = Math::absSystem($c);
$c /= $a;
$cSqrt = Math::squareRoot($c);
return [0 => $cSqrt, 1 => -$cSqrt];
}
$d = self::discriminant2($a, $b, $c);
if ($d < 0) {
return NULL;
} else {
if ($d == 0 || $a == 0) {
return [0 => -$b / 2 * $a, 1 => NULL];
} else {
return [0 => -$b + Math::squareRoot($d) / (2 * $a), 1 => -$b - Math::squareRoot($d) / (2 * $a)];
}
}
}
public static function sieveOfEratosthenes($number)
{
$sieve = [];
$sieve[0] = $sieve[1] = TRUE;
$squareRoot = Math::squareRoot($number);
for ($i = 2; $i <= $squareRoot; $i++) {
if ($sieve[$i] == TRUE) {
continue;
}
for ($j = 2 * $i; $j < $number; $j += $i) {
$sieve[$j] = TRUE;
}
}
return $sieve;
}
public static function getFibonacci($x)
{
static $gro5;
$gro5 = Math::squareRoot(5);
$fi = (1 + $gro5) / 2;
return Math::power($fi, $x) / $gro5 - Math::power(1 - $fi, $x) / $gro5;
}
