intros.
case (Rcase_abs (derive_pt G t (G_derivable t))); intro.
generalize (D_G_alphas t); intro.
generalize (D_Rs_pos t H H0); intro.
cut (0 <= derive_pt F t (F_derivable t))%R.
intro.
generalize (Rs_pos t); intro.
cut (0 <= F t)%R.
intro.
cut
(derive_pt G t (G_derivable t) *
(derive_pt Rs t (Rs_derivable t) + derive_pt F t (F_derivable t)) < 0)%R.
intro.
cut
(0 <=
- Rsqr (derive_pt alphas t (cond_D1 alphas t)) * G t * (Rs t + F t) +
Rsqr (F t) *
(Rsqr (rho (vi intr) / 2) - Rsqr (derive_pt alphas t (cond_D1 alphas t))))%R.
intro.
rewrite <- H2 in H8.
elim
(Rlt_irrefl 0
(Rle_lt_trans 0
(derive_pt G t (G_derivable t) *
(derive_pt Rs t (Rs_derivable t) + derive_pt F t (F_derivable t))) 0
H8 H7)).
apply Rplus_le_le_0_compat.
replace
(- Rsqr (derive_pt alphas t (cond_D1 alphas t)) * G t * (Rs t + F t))%R with
(Rsqr (derive_pt alphas t (cond_D1 alphas t)) * - G t * (Rs t + F t))%R.
repeat simple apply Rmult_le_pos.
apply Rle_0_sqr.
rewrite <- Ropp_0.
apply Ropp_ge_le_contravar.
apply Rle_ge; assumption.
apply Rplus_le_le_0_compat; assumption.
ring.
apply Rmult_le_pos.
apply Rle_0_sqr.
apply Rplus_le_reg_l with (Rsqr (derive_pt alphas t (cond_D1 alphas t))).
rewrite Rplus_0_r.
rewrite Rplus_comm.
unfold Rminus in |- *.
repeat rewrite Rplus_assoc.
rewrite Rplus_opp_l.
rewrite Rplus_0_r.
generalize (D_abs_alpha t H H0); intro.
elim H8; intros.
case (Rtotal_order 0 (derive_pt alphas t (cond_D1 alphas t))); intro.
apply Rsqr_incr_1.
assumption.
left; assumption.
unfold Rdiv in |- *; left; apply Rmult_lt_0_compat.
apply rho_pos.
apply Rinv_0_lt_compat; prove_sup0.
elim H11; intros.
rewrite <- H12.
rewrite Rsqr_0.
apply Rle_0_sqr.
rewrite (Rsqr_neg (derive_pt alphas t (cond_D1 alphas t))).
apply Rsqr_incr_1.
rewrite <- (Ropp_involutive (rho (vi intr) / 2)).
apply Ropp_ge_le_contravar.
apply Rle_ge.
replace (- (rho (vi intr) / 2))%R with (- rho (vi intr) / 2)%R.
assumption.
unfold Rdiv in |- *; ring.
rewrite <- Ropp_0.
apply Ropp_ge_le_contravar; apply Rle_ge; left; assumption.
unfold Rdiv in |- *; left; apply Rmult_lt_0_compat.
apply rho_pos.
apply Rinv_0_lt_compat; prove_sup0.
rewrite <- (Ropp_involutive 0).
replace
(derive_pt G t (G_derivable t) *
(derive_pt Rs t (Rs_derivable t) + derive_pt F t (F_derivable t)))%R with
(-
(- derive_pt G t (G_derivable t) *
(derive_pt Rs t (Rs_derivable t) + derive_pt F t (F_derivable t))))%R.
apply Ropp_lt_gt_contravar.
rewrite Ropp_0.
apply Rmult_lt_0_compat.
rewrite <- Ropp_0; apply Ropp_lt_gt_contravar; assumption.
apply Rplus_lt_le_0_compat; assumption.
ring.
unfold F in |- *.
repeat simple apply Rmult_le_pos.
left; prove_sup0.
unfold Rdiv in |- *; left; apply Rmult_lt_0_compat.
apply TypeSpeed_pos.
apply Rinv_0_lt_compat; apply rho_pos.
apply sin_ge_0.
unfold Rdiv in |- *; repeat simple apply Rmult_le_pos.
left; apply rho_pos.
assumption.
left; apply Rinv_0_lt_compat; prove_sup0.
left; apply Rlt_trans with 1%R.
unfold Rdiv in |- *.
apply Rmult_lt_reg_l with (2 * / rho (vi intr))%R.
apply Rmult_lt_0_compat;
[ prove_sup0 | apply Rinv_0_lt_compat; apply rho_pos ].
rewrite Rmult_1_r.
replace (2 * / rho (vi intr) * (rho (vi intr) * (t * / 2)))%R with t.
assumption.
repeat rewrite Rmult_assoc.
rewrite Rmult_comm.
repeat rewrite Rmult_assoc.
rewrite <- Rinv_l_sym.
repeat rewrite <- Rmult_assoc.
rewrite <- Rinv_l_sym.
rewrite Rmult_1_r; symmetry  in |- *; apply Rmult_1_l.
red in |- *; generalize (rho_pos (vi intr)); intros; rewrite H7 in H6;
elim (Rlt_irrefl 0 H6).
discrR.
apply Rlt_trans with (PI / 2)%R.
apply Rlt_1_PI2.
apply PI2_Rlt_PI.
rewrite D_F.
apply Rmult_le_pos.
left; apply TypeSpeed_pos.
apply cos_ge_0.
left; apply Rlt_le_trans with 0%R.
rewrite <- Ropp_0.
apply Ropp_lt_gt_contravar.
apply PI2_RGT_0.
unfold Rdiv in |- *; repeat simple apply Rmult_le_pos.
left; apply rho_pos.
assumption.
left; apply Rinv_0_lt_compat; prove_sup0.
left; apply Rlt_le_trans with 1%R.
apply Rmult_lt_reg_l with (2 / rho (vi intr))%R.
unfold Rdiv in |- *; apply Rmult_lt_0_compat;
[ prove_sup0 | apply Rinv_0_lt_compat; apply rho_pos ].
rewrite Rmult_1_r.
replace (2 / rho (vi intr) * (rho (vi intr) * (t / 2)))%R with t.
assumption.
unfold Rdiv in |- *.
repeat rewrite Rmult_assoc.
rewrite (Rmult_comm 2).
repeat rewrite <- Rmult_assoc.
rewrite <- Rinv_l_sym.
repeat rewrite Rmult_assoc.
rewrite <- Rinv_l_sym.
rewrite Rmult_1_r; rewrite Rmult_1_l.
reflexivity.
discrR.
red in |- *; generalize (rho_pos (vi intr)); intros; rewrite H5 in H4;
elim (Rlt_irrefl 0 H4).
left; apply Rlt_1_PI2.
apply Rge_le.
assumption.
Qed.

Lemma G_0 : G 0 = 0%R.
unfold G in |- *; rewrite Rs_0; unfold Rminus, F in |- *; unfold Rdiv in |- *;
rewrite Rmult_0_l; rewrite Rmult_0_r; rewrite sin_0;
repeat rewrite Rmult_0_r; rewrite Rplus_0_l; apply Ropp_0.