intros e n H'0.
replace (Zsucc n) with (n + Zsucc 0)%Z.
rewrite powerRZ_add; auto.
rewrite powerRZ_1.
rewrite Rmult_comm; auto.
auto with zarith.
Qed.
(* Conversion theorem between relative numbers and reals *)

Theorem Zpower_nat_Z_powerRZ :
forall (n : Z) (m : nat),
IZR (Zpower_nat n m) = powerRZ (IZR n) (Z_of_nat m).