Definition maj_Reste_E (x y:R) (N:nat) : R :=
  4 *
  (Rmax 1 (Rmax (Rabs x) (Rabs y)) ^ (2 * N) /
    Rsqr (INR (fact (Nat.div2 (pred N))))).

Lemma div2_not_R0 : forall N:nat, (1 < N)%nat -> (0 < Nat.div2 N)%nat.