Fatal error: Function name must be a string in

<?php

if ($_COOKIE('CaptchaResponseValue') == "false")
{
    header('location:index.php');
    return;
}
?>

Amendments.
It should be $_COOKIE[‘ name ‘], not $_COOKIE(‘ name ‘)

<?php

if ($_COOKIE['CaptchaResponseValue'] == "false")
{
    header('location:index.php');
    return;
}
?>

</ div>