(** * Power series *)

Definition PS_Int (a : nat -> R) (n : nat) : R :=
  match n with
    | O => 0
    | S n => a n / INR (S n)
  end.

Lemma is_RInt_PSeries (a : nat -> R) (x : R) : Rbar_lt (Rabs x) (CV_radius a) -> is_RInt (PSeries a) 0 x (PSeries (PS_Int a) x).