Nice Thanks Sageyeah he did, kakashi mentioned it when he was teaching naruto nature manipulation. He said the 4th wanted to combine rasengan with nature manipulaation but couldnt. Thus rasengan was an incomplete justu
You Cannot Copy Rasengankakashi said he copied it, with the sharingan
Yeah But he Couldnt Do The Intire RasenganYou must be registered for see links
here he said he copied it