(** *** Composition *)
(** Composition with linear functions *)

Lemma Derive_n_comp_opp (f : R -> R) (n : nat) (x : R) :
locally (- x) (fun y => (forall k, (k <= n)%nat -> ex_derive_n f k y)) ->
Derive_n (fun y => f (- y)) n x  = ((-1) ^ n * Derive_n f n (-x)).