proposition: Lemma derive_pt_Rball_opp: forall f c r x pr pr', Rball c r x -> derive_pt_in (Rball c r) (- f)%F x pr = - derive_pt_in (Rball c r) f x pr'.
proof: Proof. intros f c r x [] [] x_in ; eapply derivable_pt_lim_Rball_uniqueness, derivable_pt_lim_in_opp ; eassumption. Qed.
imports: Rbase Ranalysis Rinterval Rfunctions Rfunction_def Rfunction_facts Ranalysis_def Ranalysis_def_simpl Ranalysis_continuity MyRIneq MyR_dist Lra Tactics