fact: Definition Bertrand alpha beta A B (I : R) := is_RInt (fun x => powerRZ x alpha * (pow (ln x) beta)) A B I.
imports: Coq(Reals ZArith Psatz Fourier_util) Flocq(Raux) Coquelicot(Coquelicot AutoDerive) mathcomp.ssreflect(ssreflect ssrfun ssrbool ssrnat bigop) Stdlib Coquelicot Xreal Interval