@andmail 

Thanks, it works

 Dear @Joe Riel

It does not seem to work for me (Maple 2020). Is there a rule for having text or math or something like that for "(*", "*)"? (I tried math and text both). I am using whorksheet.

Best regards,

 Thank you @ecterrab

There is a problem one deletes the equation with Ctrl+delete. After a complete reevaluation of the whole document, the equation label seems to disappear. Is there a way to keep it in place after a reevaluation?

Regards

@adel-00 

I think it depends on if the function has a primitive or not. The function that you have gives error function which is computied numerically. This is why @reply proposes a sweep of a