With the substitution You obtain...
(1)
... where the s variable is 'pulled out' the integral so that integration [by parts...] is more confortable...
Kind regards
My unsuccessful attempt:
Integration by parts:
Using "liate":
Using L'Hopital on the limit I get that the limit is equal to 0. So...
I use integration by parts again and I get...
The answer is supposed to be
Where did I go wrong?