apply H1; rewrite H2; ring.
Qed.

(* Specifications: *)
Lemma Rmult_neq_compat_r: forall  r1 r2 r3:R, (r1 <> 0)%R -> (r2 <> r3)%R
-> (r2 *r1 <> r3*r1)%R.
Lemma Rmult_neq_compat_r: forall  r1 r2 r3:R, (r1 <> 0)%R -> (r2 <> r3)%R
-> (r2 *r1 <> r3*r1)%R.