Quiz

No. These integral sines and exponentials are calculated through the sum of a series, of course, but in this specific case, it's not necessary. Here, I even looked up a solution on Habr: https://habrahabr.ru/post/146140/ (look from "The tale begins to unfold"). ---------- Oh, and it can be obtained normally through the Dirichlet integral. But I've forgotten the Dirichlet integral too much to come up with this solution yesterday...