proposition: Lemma D_infty_scal : forall f a, D_infty f -> D_infty (mult_real_fct a f).
proof: Proof. intros f a Df n ; apply D_scal ; trivial. Qed.
imports: Rbase Ranalysis Lia Lra Rfunctions Rfunction_facts Rextensionality Rinterval Ranalysis_def Ranalysis_def_simpl Ranalysis_facts Ranalysis_continuity Ranalysis_derivability Ranalysis_monotonicity Rfunction_classes_def MyR_dist Reals.Tactics