case H; intros.
- red; left.
apply Rlt_mult_inv_pos; auto with real.
- rewrite <- H1.
red; right; ring.
Qed.

Lemma inv_sqrt_depr x : 0 < x -> / sqrt x = sqrt (/ x).
#[deprecated(since="8.16",note="Use sqrt_inv.")]
Notation inv_sqrt := inv_sqrt_depr.