I do hope someone could solve this problem. Waiting...

Thanks for replying. Unfortunately, the place I can access the Internet is off-campus, so I cannot view the article which you give the link of. I wonder whether you can send a copy to my email box? Dust you are, to dust you shall return.

I copy your statement in Maple and after a few minutes Maple returned the result(it seems to be too long): ADMIN EDIT: Maple output removed: It was very long and made this thread unreadable. If you wish to post large outputs, please upload the worksheet using the filemanager. And it seems no warnings appeared. Dust you are, to dust you shall return.