proposition: Lemma derive_pt_opp_rev : forall f (x:R) (pr1:derivable_pt (- f) x), derive_pt (- f) x pr1 = - derive_pt f x (derivable_pt_opp_rev _ _ pr1).
proof: Proof. intros. apply derive_pt_eq_0. apply derivable_pt_lim_opp_fwd. rewrite Ropp_involutive. apply (derive_pt_eq_1 _ _ _ (derivable_pt_opp_rev _ _ pr1)). reflexivity. Qed.
imports: Rbase Rfunctions Rlimit Rderiv