intros; unfold rho in |- *; apply Rmult_lt_compat_l;
[ apply g_pos
| unfold Rdiv in |- *; apply Rmult_lt_compat_l;
[ apply tan_MaxBank_pos
| apply
(Rinv_lt_contravar h1 h2
(Rmult_lt_0_compat h1 h2 (TypeSpeed_pos h1) (TypeSpeed_pos h2)) H) ] ].
Qed.

(**********)
Lemma r_stric_increasing :
forall h1 h2 : TypeSpeed, (h1 < h2)%R -> (r h1 < r h2)%R.