proposition: Lemma derivable_pt_xlnx x (x_pos : 0 < x) : derivable_pt xlnx x.
proof: Proof. apply (@derivable_f_eq_g _ _ x 0 xlnx_total_xlnx x_pos (derivable_xlnx_total x_pos)). Defined.
imports: mathcomp(all_ssreflect ssralg ssrnum) mathcomp(Rstruct) Reals Lra ssrR realType_ext Reals_ext Ranalysis_ext logb convex