/**
  * Renders a cross product
  *
  * @param object $obj mathPHP object
  * @return string html sourcecode
  */
 public static function rendercross($obj)
 {
     if (!is_object($obj->getSourceCode()["veca"])) {
         $veca = math::vector($obj->getSourceCode()["veca"]);
     } else {
         $veca = $obj->getSourceCode()["veca"];
     }
     if (!is_object($obj->getSourceCode()["vecb"])) {
         $vecb = math::vector($obj->getSourceCode()["vecb"]);
     } else {
         $vecb = $obj->getSourceCode()["vecb"];
     }
     $veca->setIsRenderingstarted();
     $vecb->setIsRenderingstarted();
     if (is_string($veca->getContent()["name"]) && !empty($veca->getContent()["name"]) && !empty($vecb->getContent()["name"]) && is_string($vecb->getContent()["name"])) {
         $q = render::objectToSourececode($veca->getSourceCode()["name"], "vec") . render::objectToSourececode("", "cross") . render::objectToSourececode($vecb->getSourceCode()["name"], "vec") . render::objectToSourececode("", "eqq");
     } else {
         $q = "";
     }
     $veca->setSourceCode(false, "name");
     $vecb->setSourceCode(false, "name");
     $q .= render::objectToSourececode($veca, "vector") . render::objectToSourececode("", "cross") . render::objectToSourececode($vecb, "vector") . render::objectToSourececode("", "eqq") . render::doRendering([internal\funcs::kreuzProductAusrechnen($veca, $vecb)]);
     return $q;
 }