Dear Carlo, thank you for your kind support.

I know, thank you very much. However, the important thing for me here, Can I apply Hopital rule to get this 1/2.

Dear Carlo, thank you very much for your very different approach. It is very interesting. On the other hand, what do you think that can we apply Hopital rule, because of the result which we have obtained on develop.wolframcloud.com ? Also please remember, we know that the limit appearance of the left side is $0/0$ (under $u → ∞$) .