proposition: Lemma Rsqrt_mult_distr : forall (x y z : nonnegreal), x * y = z -> Rsqrt z = Rsqrt x * Rsqrt y.
proof: Proof. intros x y z Heq ; apply Rsqr_inj. apply Rsqrt_positivity. apply Rmult_le_pos ; apply Rsqrt_positivity. rewrite Rsqr_mult. unfold Rsqr ; do 3 rewrite Rsqrt_Rsqrt ; auto. Qed.
imports: Reals MyRIneq Fourier Lia Lra Rsequence_usual_facts