proposition: Lemma derive_expR : 'D_1 expR = expR :> (R -> R).
proof: Proof. by apply/funext => r /=; rewrite derive_val. Qed.
imports: mathcomp(all_ssreflect ssralg ssrint ssrnum matrix) mathcomp(interval rat) mathcomp(boolp classical_sets functions) mathcomp(mathcomp_extra) reals ereal signed topology normedtype landau sequences derive realfun itv convex