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(* modify it under the terms of the GNU Lesser General Public License *)
(* as published by the Free Software Foundation; either version 2.1   *)
(* of the License, or (at your option) any later version.             *)
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(* This program is distributed in the hope that it will be useful,    *)
(* but WITHOUT ANY WARRANTY; without even the implied warranty of     *)
(* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the      *)
(* GNU General Public License for more details.                       *)
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(* You should have received a copy of the GNU Lesser General Public   *)
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(* 02110-1301 USA                                                     *)
Record Trajectory : Type := mkTrajectory
{x : Differential;
y : Differential;
theta : Differential;
phi : Differential;
h : TypeSpeed;
cond_x :
forall t : R, derive_pt x t (cond_diff x t) = (h * cos (theta t))%R;
cond_y :
forall t : R, derive_pt y t (cond_diff y t) = (h * sin (theta t))%R;
cond_phi : forall t : R, (- MaxBank <= phi t <= MaxBank)%R;
cond_theta :
forall t : R,
derive_pt theta t (cond_diff theta t) = (g * (tan (phi t) / h))%R}.
Record EvaderTrajectory : Type := mkEvaderTrajectory
{tr : Trajectory;
tr_cond1 : forall t : R, x tr t = (x tr 0 + h tr * t)%R;
tr_cond2 : forall t : R, y tr t = y tr 0%R;
tr_cond3 : forall t : R, theta tr t = 0%R;
tr_cond4 : forall t : R, phi tr t = 0%R}.
intro; reg.
Qed.
intro; reg.
Qed.
intros; reg.
rewrite cos_0; ring.
Qed.
intros; reg.
rewrite sin_0; ring.
Qed.
intros; simpl in |- *; cut (0 < MaxBank)%R.
split.
left; rewrite <- Ropp_0; apply Ropp_lt_gt_contravar; assumption.
left; assumption.
unfold MaxBank in |- *; unfold Rdiv in |- *; apply Rmult_lt_0_compat;
[ prove_sup | apply Rinv_0_lt_compat; prove_sup ].
Qed.

Lemma fct_der1 : forall t : R, derivable_pt (fun t : R => 0%R) t.