Litipk\BigNumbers\Decimal::cotan PHP 메소드

    public function cotan($scale = null)
    {
        $sin = $this->sin($scale + 2);
        if ($sin->isZero()) {
            throw new \DomainException("The cotangent of this 'angle' is undefined.");
        }
        return $this->cos($scale + 2)->div($sin)->round($scale);
    }