diff options
Diffstat (limited to 'theories/Reals/Rtrigo1.v')
| -rw-r--r-- | theories/Reals/Rtrigo1.v | 383 |
1 files changed, 102 insertions, 281 deletions
diff --git a/theories/Reals/Rtrigo1.v b/theories/Reals/Rtrigo1.v index 4d241863..bf00f736 100644 --- a/theories/Reals/Rtrigo1.v +++ b/theories/Reals/Rtrigo1.v @@ -1,9 +1,11 @@ (************************************************************************) -(* v * The Coq Proof Assistant / The Coq Development Team *) -(* <O___,, * INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2016 *) +(* * The Coq Proof Assistant / The Coq Development Team *) +(* v * INRIA, CNRS and contributors - Copyright 1999-2018 *) +(* <O___,, * (see CREDITS file for the list of authors) *) (* \VV/ **************************************************************) -(* // * This file is distributed under the terms of the *) -(* * GNU Lesser General Public License Version 2.1 *) +(* // * This file is distributed under the terms of the *) +(* * GNU Lesser General Public License Version 2.1 *) +(* * (see LICENSE file for the text of the license) *) (************************************************************************) Require Import Rbase. @@ -182,13 +184,10 @@ destruct (pre_cos_bound _ 0 lo up) as [_ upper]. apply Rle_lt_trans with (1 := upper). apply Rlt_le_trans with (2 := lower). unfold cos_approx, sin_approx. -simpl sum_f_R0; replace 7 with (IZR 7) by (simpl; field). -replace 8 with (IZR 8) by (simpl; field). +simpl sum_f_R0. unfold cos_term, sin_term; simpl fact; rewrite !INR_IZR_INZ. -simpl plus; simpl mult. -field_simplify; - try (repeat apply conj; apply not_eq_sym, Rlt_not_eq, (IZR_lt 0); reflexivity). -unfold Rminus; rewrite !pow_IZR, <- !mult_IZR, <- !opp_IZR, <- ?plus_IZR. +simpl plus; simpl mult; simpl Z_of_nat. +field_simplify. match goal with |- IZR ?a / ?b < ?c / ?d => apply Rmult_lt_reg_r with d;[apply (IZR_lt 0); reflexivity | @@ -198,7 +197,7 @@ match goal with end. unfold Rdiv; rewrite !Rmult_assoc, Rinv_l, Rmult_1_r; [ | apply not_eq_sym, Rlt_not_eq, (IZR_lt 0); reflexivity]. -repeat (rewrite <- !plus_IZR || rewrite <- !mult_IZR). +rewrite <- !mult_IZR. apply IZR_lt; reflexivity. Qed. @@ -323,6 +322,7 @@ Lemma sin_PI : sin PI = 0. Proof. assert (H := sin2_cos2 PI). rewrite cos_PI in H. + change (-1) with (-(1)) in H. rewrite <- Rsqr_neg in H. rewrite Rsqr_1 in H. cut (Rsqr (sin PI) = 0). @@ -533,9 +533,8 @@ Qed. Lemma sin_PI_x : forall x:R, sin (PI - x) = sin x. Proof. - intro x; rewrite sin_minus; rewrite sin_PI; rewrite cos_PI; rewrite Rmult_0_l; - unfold Rminus in |- *; rewrite Rplus_0_l; rewrite Ropp_mult_distr_l_reverse; - rewrite Ropp_involutive; apply Rmult_1_l. + intro x; rewrite sin_minus; rewrite sin_PI; rewrite cos_PI. + ring. Qed. Lemma sin_period : forall (x:R) (k:nat), sin (x + 2 * INR k * PI) = sin x. @@ -593,9 +592,9 @@ Proof. generalize (Rsqr_incrst_1 1 (sin x) H (Rlt_le 0 1 Rlt_0_1) (Rlt_le 0 (sin x) (Rlt_trans 0 1 (sin x) Rlt_0_1 H))); - rewrite Rsqr_1; intro; rewrite sin2 in H0; unfold Rminus in H0; + rewrite Rsqr_1; intro; rewrite sin2 in H0; unfold Rminus in H0. generalize (Rplus_lt_compat_l (-1) 1 (1 + - Rsqr (cos x)) H0); - repeat rewrite <- Rplus_assoc; repeat rewrite Rplus_opp_l; + repeat rewrite <- Rplus_assoc; change (-1) with (-(1)); rewrite Rplus_opp_l; rewrite Rplus_0_l; intro; rewrite <- Ropp_0 in H1; generalize (Ropp_lt_gt_contravar (-0) (- Rsqr (cos x)) H1); repeat rewrite Ropp_involutive; intro; generalize (Rle_0_sqr (cos x)); @@ -603,6 +602,7 @@ Proof. auto with real. cut (sin x < -1). intro; generalize (Ropp_lt_gt_contravar (sin x) (-1) H); + change (-1) with (-(1)); rewrite Ropp_involutive; clear H; intro; generalize (Rsqr_incrst_1 1 (- sin x) H (Rlt_le 0 1 Rlt_0_1) @@ -610,7 +610,7 @@ Proof. rewrite Rsqr_1; intro; rewrite <- Rsqr_neg in H0; rewrite sin2 in H0; unfold Rminus in H0; generalize (Rplus_lt_compat_l (-1) 1 (1 + - Rsqr (cos x)) H0); - repeat rewrite <- Rplus_assoc; repeat rewrite Rplus_opp_l; + rewrite <- Rplus_assoc; change (-1) with (-(1)); rewrite Rplus_opp_l; rewrite Rplus_0_l; intro; rewrite <- Ropp_0 in H1; generalize (Ropp_lt_gt_contravar (-0) (- Rsqr (cos x)) H1); repeat rewrite Ropp_involutive; intro; generalize (Rle_0_sqr (cos x)); @@ -696,41 +696,38 @@ Proof. rewrite <- Rinv_l_sym. do 2 rewrite Rmult_1_r; apply Rle_lt_trans with (INR (fact (2 * n + 1)) * 4). apply Rmult_le_compat_l. - replace 0 with (INR 0); [ idtac | reflexivity ]; apply le_INR; apply le_O_n. - simpl in |- *; rewrite Rmult_1_r; replace 4 with (Rsqr 2); - [ idtac | ring_Rsqr ]; replace (a * a) with (Rsqr a); - [ idtac | reflexivity ]; apply Rsqr_incr_1. + apply pos_INR. + simpl in |- *; rewrite Rmult_1_r; change 4 with (Rsqr 2); + apply Rsqr_incr_1. apply Rle_trans with (PI / 2); [ assumption | unfold Rdiv in |- *; apply Rmult_le_reg_l with 2; [ prove_sup0 | rewrite <- Rmult_assoc; rewrite Rinv_r_simpl_m; - [ replace 4 with 4; [ apply PI_4 | ring ] | discrR ] ] ]. + [ apply PI_4 | discrR ] ] ]. left; assumption. left; prove_sup0. rewrite H1; replace (2 * n + 1 + 2)%nat with (S (S (2 * n + 1))). do 2 rewrite fact_simpl; do 2 rewrite mult_INR. repeat rewrite <- Rmult_assoc. rewrite <- (Rmult_comm (INR (fact (2 * n + 1)))). - rewrite Rmult_assoc. apply Rmult_lt_compat_l. apply lt_INR_0; apply neq_O_lt. assert (H2 := fact_neq_0 (2 * n + 1)). red in |- *; intro; elim H2; symmetry in |- *; assumption. do 2 rewrite S_INR; rewrite plus_INR; rewrite mult_INR; set (x := INR n); unfold INR in |- *. - replace ((2 * x + 1 + 1 + 1) * (2 * x + 1 + 1)) with (4 * x * x + 10 * x + 6); + replace (((1 + 1) * x + 1 + 1 + 1) * ((1 + 1) * x + 1 + 1)) with (4 * x * x + 10 * x + 6); [ idtac | ring ]. - apply Rplus_lt_reg_l with (-4); rewrite Rplus_opp_l; - replace (-4 + (4 * x * x + 10 * x + 6)) with (4 * x * x + 10 * x + 2); + apply Rplus_lt_reg_l with (-(4)); rewrite Rplus_opp_l; + replace (-(4) + (4 * x * x + 10 * x + 6)) with (4 * x * x + 10 * x + 2); [ idtac | ring ]. apply Rplus_le_lt_0_compat. cut (0 <= x). intro; apply Rplus_le_le_0_compat; repeat apply Rmult_le_pos; assumption || left; prove_sup. - unfold x in |- *; replace 0 with (INR 0); - [ apply le_INR; apply le_O_n | reflexivity ]. - prove_sup0. + apply pos_INR. + now apply IZR_lt. ring. apply INR_fact_neq_0. apply INR_fact_neq_0. @@ -738,39 +735,33 @@ Proof. Qed. Lemma SIN : forall a:R, 0 <= a -> a <= PI -> sin_lb a <= sin a <= sin_ub a. +Proof. intros; unfold sin_lb, sin_ub in |- *; apply (sin_bound a 1 H H0). Qed. Lemma COS : forall a:R, - PI / 2 <= a -> a <= PI / 2 -> cos_lb a <= cos a <= cos_ub a. +Proof. intros; unfold cos_lb, cos_ub in |- *; apply (cos_bound a 1 H H0). Qed. (**********) Lemma _PI2_RLT_0 : - (PI / 2) < 0. Proof. - rewrite <- Ropp_0; apply Ropp_lt_contravar; apply PI2_RGT_0. + assert (H := PI_RGT_0). + fourier. Qed. Lemma PI4_RLT_PI2 : PI / 4 < PI / 2. Proof. - unfold Rdiv in |- *; apply Rmult_lt_compat_l. - apply PI_RGT_0. - apply Rinv_lt_contravar. - apply Rmult_lt_0_compat; prove_sup0. - pattern 2 at 1 in |- *; rewrite <- Rplus_0_r. - replace 4 with (2 + 2); [ apply Rplus_lt_compat_l; prove_sup0 | ring ]. + assert (H := PI_RGT_0). + fourier. Qed. Lemma PI2_Rlt_PI : PI / 2 < PI. Proof. - unfold Rdiv in |- *; pattern PI at 2 in |- *; rewrite <- Rmult_1_r. - apply Rmult_lt_compat_l. - apply PI_RGT_0. - pattern 1 at 3 in |- *; rewrite <- Rinv_1; apply Rinv_lt_contravar. - rewrite Rmult_1_l; prove_sup0. - pattern 1 at 1 in |- *; rewrite <- Rplus_0_r; apply Rplus_lt_compat_l; - apply Rlt_0_1. + assert (H := PI_RGT_0). + fourier. Qed. (***************************************************) @@ -787,12 +778,10 @@ Proof. rewrite H3; rewrite sin_PI2; apply Rlt_0_1. rewrite <- sin_PI_x; generalize (Ropp_gt_lt_contravar x (PI / 2) H3); intro H4; generalize (Rplus_lt_compat_l PI (- x) (- (PI / 2)) H4). - replace (PI + - x) with (PI - x). replace (PI + - (PI / 2)) with (PI / 2). intro H5; generalize (Ropp_lt_gt_contravar x PI H0); intro H6; change (- PI < - x) in H6; generalize (Rplus_lt_compat_l PI (- PI) (- x) H6). rewrite Rplus_opp_r. - replace (PI + - x) with (PI - x). intro H7; elim (SIN (PI - x) (Rlt_le 0 (PI - x) H7) @@ -800,9 +789,7 @@ Proof. intros H8 _; generalize (sin_lb_gt_0 (PI - x) H7 (Rlt_le (PI - x) (PI / 2) H5)); intro H9; apply (Rlt_le_trans 0 (sin_lb (PI - x)) (sin (PI - x)) H9 H8). - reflexivity. - pattern PI at 2 in |- *; rewrite double_var; ring. - reflexivity. + field. Qed. Theorem cos_gt_0 : forall x:R, - (PI / 2) < x -> x < PI / 2 -> 0 < cos x. @@ -855,16 +842,12 @@ Proof. rewrite <- (Ropp_involutive (cos x)); apply Ropp_le_ge_contravar; rewrite <- neg_cos; replace (x + PI) with (x - PI + 2 * INR 1 * PI). rewrite cos_period; apply cos_ge_0. - replace (- (PI / 2)) with (- PI + PI / 2). + replace (- (PI / 2)) with (- PI + PI / 2) by field. unfold Rminus in |- *; rewrite (Rplus_comm x); apply Rplus_le_compat_l; assumption. - pattern PI at 1 in |- *; rewrite (double_var PI); rewrite Ropp_plus_distr; - ring. unfold Rminus in |- *; rewrite Rplus_comm; - replace (PI / 2) with (- PI + 3 * (PI / 2)). + replace (PI / 2) with (- PI + 3 * (PI / 2)) by field. apply Rplus_le_compat_l; assumption. - pattern PI at 1 in |- *; rewrite (double_var PI); rewrite Ropp_plus_distr; - ring. unfold INR in |- *; ring. Qed. @@ -905,16 +888,12 @@ Proof. apply Ropp_lt_gt_contravar; rewrite <- neg_cos; replace (x + PI) with (x - PI + 2 * INR 1 * PI). rewrite cos_period; apply cos_gt_0. - replace (- (PI / 2)) with (- PI + PI / 2). + replace (- (PI / 2)) with (- PI + PI / 2) by field. unfold Rminus in |- *; rewrite (Rplus_comm x); apply Rplus_lt_compat_l; assumption. - pattern PI at 1 in |- *; rewrite (double_var PI); rewrite Ropp_plus_distr; - ring. unfold Rminus in |- *; rewrite Rplus_comm; - replace (PI / 2) with (- PI + 3 * (PI / 2)). + replace (PI / 2) with (- PI + 3 * (PI / 2)) by field. apply Rplus_lt_compat_l; assumption. - pattern PI at 1 in |- *; rewrite (double_var PI); rewrite Ropp_plus_distr; - ring. unfold INR in |- *; ring. Qed. @@ -951,7 +930,7 @@ Lemma cos_ge_0_3PI2 : forall x:R, 3 * (PI / 2) <= x -> x <= 2 * PI -> 0 <= cos x. Proof. intros; rewrite <- cos_neg; rewrite <- (cos_period (- x) 1); - unfold INR in |- *; replace (- x + 2 * 1 * PI) with (2 * PI - x). + unfold INR in |- *; replace (- x + 2 * 1 * PI) with (2 * PI - x) by ring. generalize (Ropp_le_ge_contravar x (2 * PI) H0); intro H1; generalize (Rge_le (- x) (- (2 * PI)) H1); clear H1; intro H1; generalize (Rplus_le_compat_l (2 * PI) (- (2 * PI)) (- x) H1). @@ -960,36 +939,30 @@ Proof. generalize (Rge_le (- (3 * (PI / 2))) (- x) H3); clear H3; intro H3; generalize (Rplus_le_compat_l (2 * PI) (- x) (- (3 * (PI / 2))) H3). - replace (2 * PI + - (3 * (PI / 2))) with (PI / 2). + replace (2 * PI + - (3 * (PI / 2))) with (PI / 2) by field. intro H4; apply (cos_ge_0 (2 * PI - x) (Rlt_le (- (PI / 2)) (2 * PI - x) (Rlt_le_trans (- (PI / 2)) 0 (2 * PI - x) _PI2_RLT_0 H2)) H4). - rewrite double; pattern PI at 2 3 in |- *; rewrite double_var; ring. - ring. Qed. Lemma form1 : forall p q:R, cos p + cos q = 2 * cos ((p - q) / 2) * cos ((p + q) / 2). Proof. intros p q; pattern p at 1 in |- *; - replace p with ((p - q) / 2 + (p + q) / 2). - rewrite <- (cos_neg q); replace (- q) with ((p - q) / 2 - (p + q) / 2). + replace p with ((p - q) / 2 + (p + q) / 2) by field. + rewrite <- (cos_neg q); replace (- q) with ((p - q) / 2 - (p + q) / 2) by field. rewrite cos_plus; rewrite cos_minus; ring. - pattern q at 3 in |- *; rewrite double_var; unfold Rdiv in |- *; ring. - pattern p at 3 in |- *; rewrite double_var; unfold Rdiv in |- *; ring. Qed. Lemma form2 : forall p q:R, cos p - cos q = -2 * sin ((p - q) / 2) * sin ((p + q) / 2). Proof. intros p q; pattern p at 1 in |- *; - replace p with ((p - q) / 2 + (p + q) / 2). - rewrite <- (cos_neg q); replace (- q) with ((p - q) / 2 - (p + q) / 2). + replace p with ((p - q) / 2 + (p + q) / 2) by field. + rewrite <- (cos_neg q); replace (- q) with ((p - q) / 2 - (p + q) / 2) by field. rewrite cos_plus; rewrite cos_minus; ring. - pattern q at 3 in |- *; rewrite double_var; unfold Rdiv in |- *; ring. - pattern p at 3 in |- *; rewrite double_var; unfold Rdiv in |- *; ring. Qed. Lemma form3 : @@ -1007,11 +980,9 @@ Lemma form4 : forall p q:R, sin p - sin q = 2 * cos ((p + q) / 2) * sin ((p - q) / 2). Proof. intros p q; pattern p at 1 in |- *; - replace p with ((p - q) / 2 + (p + q) / 2). - pattern q at 3 in |- *; replace q with ((p + q) / 2 - (p - q) / 2). + replace p with ((p - q) / 2 + (p + q) / 2) by field. + pattern q at 3 in |- *; replace q with ((p + q) / 2 - (p - q) / 2) by field. rewrite sin_plus; rewrite sin_minus; ring. - pattern q at 3 in |- *; rewrite double_var; unfold Rdiv in |- *; ring. - pattern p at 3 in |- *; rewrite double_var; unfold Rdiv in |- *; ring. Qed. @@ -1067,13 +1038,13 @@ Proof. repeat rewrite (Rmult_comm (/ 2)). clear H4; intro H4; generalize (Rplus_le_compat (- (PI / 2)) x (- (PI / 2)) y H H1); - replace (- (PI / 2) + - (PI / 2)) with (- PI). + replace (- (PI / 2) + - (PI / 2)) with (- PI) by field. intro H5; generalize (Rmult_le_compat_l (/ 2) (- PI) (x + y) (Rlt_le 0 (/ 2) (Rinv_0_lt_compat 2 Hyp)) H5). - replace (/ 2 * (x + y)) with ((x + y) / 2). - replace (/ 2 * - PI) with (- (PI / 2)). + replace (/ 2 * (x + y)) with ((x + y) / 2) by apply Rmult_comm. + replace (/ 2 * - PI) with (- (PI / 2)) by field. clear H5; intro H5; elim H4; intro H40. elim H5; intro H50. generalize (cos_gt_0 ((x + y) / 2) H50 H40); intro H6; @@ -1095,13 +1066,6 @@ Proof. rewrite H40 in H3; assert (H50 := cos_PI2); unfold Rdiv in H50; rewrite H50 in H3; rewrite Rmult_0_r in H3; rewrite Rmult_0_l in H3; elim (Rlt_irrefl 0 H3). - unfold Rdiv in |- *. - rewrite <- Ropp_mult_distr_l_reverse. - apply Rmult_comm. - unfold Rdiv in |- *; apply Rmult_comm. - pattern PI at 1 in |- *; rewrite double_var. - rewrite Ropp_plus_distr. - reflexivity. Qed. Lemma sin_increasing_1 : @@ -1111,43 +1075,42 @@ Lemma sin_increasing_1 : Proof. intros; generalize (Rplus_lt_compat_l x x y H3); intro H4; generalize (Rplus_le_compat (- (PI / 2)) x (- (PI / 2)) x H H); - replace (- (PI / 2) + - (PI / 2)) with (- PI). + replace (- (PI / 2) + - (PI / 2)) with (- PI) by field. assert (Hyp : 0 < 2). prove_sup0. intro H5; generalize (Rle_lt_trans (- PI) (x + x) (x + y) H5 H4); intro H6; generalize (Rmult_lt_compat_l (/ 2) (- PI) (x + y) (Rinv_0_lt_compat 2 Hyp) H6); - replace (/ 2 * - PI) with (- (PI / 2)). - replace (/ 2 * (x + y)) with ((x + y) / 2). + replace (/ 2 * - PI) with (- (PI / 2)) by field. + replace (/ 2 * (x + y)) with ((x + y) / 2) by apply Rmult_comm. clear H4 H5 H6; intro H4; generalize (Rplus_lt_compat_l y x y H3); intro H5; rewrite Rplus_comm in H5; generalize (Rplus_le_compat y (PI / 2) y (PI / 2) H2 H2). rewrite <- double_var. intro H6; generalize (Rlt_le_trans (x + y) (y + y) PI H5 H6); intro H7; generalize (Rmult_lt_compat_l (/ 2) (x + y) PI (Rinv_0_lt_compat 2 Hyp) H7); - replace (/ 2 * PI) with (PI / 2). - replace (/ 2 * (x + y)) with ((x + y) / 2). + replace (/ 2 * PI) with (PI / 2) by apply Rmult_comm. + replace (/ 2 * (x + y)) with ((x + y) / 2) by apply Rmult_comm. clear H5 H6 H7; intro H5; generalize (Ropp_le_ge_contravar (- (PI / 2)) y H1); rewrite Ropp_involutive; clear H1; intro H1; generalize (Rge_le (PI / 2) (- y) H1); clear H1; intro H1; generalize (Ropp_le_ge_contravar y (PI / 2) H2); clear H2; intro H2; generalize (Rge_le (- y) (- (PI / 2)) H2); clear H2; intro H2; generalize (Rplus_lt_compat_l (- y) x y H3); - replace (- y + x) with (x - y). + replace (- y + x) with (x - y) by apply Rplus_comm. rewrite Rplus_opp_l. intro H6; generalize (Rmult_lt_compat_l (/ 2) (x - y) 0 (Rinv_0_lt_compat 2 Hyp) H6); - rewrite Rmult_0_r; replace (/ 2 * (x - y)) with ((x - y) / 2). + rewrite Rmult_0_r; replace (/ 2 * (x - y)) with ((x - y) / 2) by apply Rmult_comm. clear H6; intro H6; generalize (Rplus_le_compat (- (PI / 2)) x (- (PI / 2)) (- y) H H2); - replace (- (PI / 2) + - (PI / 2)) with (- PI). - replace (x + - y) with (x - y). + replace (- (PI / 2) + - (PI / 2)) with (- PI) by field. intro H7; generalize (Rmult_le_compat_l (/ 2) (- PI) (x - y) (Rlt_le 0 (/ 2) (Rinv_0_lt_compat 2 Hyp)) H7); - replace (/ 2 * - PI) with (- (PI / 2)). - replace (/ 2 * (x - y)) with ((x - y) / 2). + replace (/ 2 * - PI) with (- (PI / 2)) by field. + replace (/ 2 * (x - y)) with ((x - y) / 2) by apply Rmult_comm. clear H7; intro H7; clear H H0 H1 H2; apply Rminus_lt; rewrite form4; generalize (cos_gt_0 ((x + y) / 2) H4 H5); intro H8; generalize (Rmult_lt_0_compat 2 (cos ((x + y) / 2)) Hyp H8); @@ -1162,23 +1125,6 @@ Proof. 2 * cos ((x + y) / 2)) H10 H8); intro H11; rewrite Rmult_0_r in H11; rewrite Rmult_comm; assumption. apply Ropp_lt_gt_contravar; apply PI2_Rlt_PI. - unfold Rdiv in |- *; apply Rmult_comm. - unfold Rdiv in |- *; rewrite <- Ropp_mult_distr_l_reverse; apply Rmult_comm. - reflexivity. - pattern PI at 1 in |- *; rewrite double_var. - rewrite Ropp_plus_distr. - reflexivity. - unfold Rdiv in |- *; apply Rmult_comm. - unfold Rminus in |- *; apply Rplus_comm. - unfold Rdiv in |- *; apply Rmult_comm. - unfold Rdiv in |- *; apply Rmult_comm. - unfold Rdiv in |- *; apply Rmult_comm. - unfold Rdiv in |- *. - rewrite <- Ropp_mult_distr_l_reverse. - apply Rmult_comm. - pattern PI at 1 in |- *; rewrite double_var. - rewrite Ropp_plus_distr. - reflexivity. Qed. Lemma sin_decreasing_0 : @@ -1193,33 +1139,16 @@ Proof. generalize (Rplus_le_compat_l (- PI) (PI / 2) x H0); generalize (Rplus_le_compat_l (- PI) y (3 * (PI / 2)) H1); generalize (Rplus_le_compat_l (- PI) (PI / 2) y H2); - replace (- PI + x) with (x - PI). - replace (- PI + PI / 2) with (- (PI / 2)). - replace (- PI + y) with (y - PI). - replace (- PI + 3 * (PI / 2)) with (PI / 2). - replace (- (PI - x)) with (x - PI). - replace (- (PI - y)) with (y - PI). + replace (- PI + x) with (x - PI) by apply Rplus_comm. + replace (- PI + PI / 2) with (- (PI / 2)) by field. + replace (- PI + y) with (y - PI) by apply Rplus_comm. + replace (- PI + 3 * (PI / 2)) with (PI / 2) by field. + replace (- (PI - x)) with (x - PI) by ring. + replace (- (PI - y)) with (y - PI) by ring. intros; change (sin (y - PI) < sin (x - PI)) in H8; - apply Rplus_lt_reg_l with (- PI); rewrite Rplus_comm; - replace (y + - PI) with (y - PI). - rewrite Rplus_comm; replace (x + - PI) with (x - PI). + apply Rplus_lt_reg_l with (- PI); rewrite Rplus_comm. + rewrite (Rplus_comm _ x). apply (sin_increasing_0 (y - PI) (x - PI) H4 H5 H6 H7 H8). - reflexivity. - reflexivity. - unfold Rminus in |- *; rewrite Ropp_plus_distr. - rewrite Ropp_involutive. - apply Rplus_comm. - unfold Rminus in |- *; rewrite Ropp_plus_distr. - rewrite Ropp_involutive. - apply Rplus_comm. - pattern PI at 2 in |- *; rewrite double_var. - rewrite Ropp_plus_distr. - ring. - unfold Rminus in |- *; apply Rplus_comm. - pattern PI at 2 in |- *; rewrite double_var. - rewrite Ropp_plus_distr. - ring. - unfold Rminus in |- *; apply Rplus_comm. Qed. Lemma sin_decreasing_1 : @@ -1233,24 +1162,14 @@ Proof. generalize (Rplus_le_compat_l (- PI) y (3 * (PI / 2)) H1); generalize (Rplus_le_compat_l (- PI) (PI / 2) y H2); generalize (Rplus_lt_compat_l (- PI) x y H3); - replace (- PI + PI / 2) with (- (PI / 2)). - replace (- PI + y) with (y - PI). - replace (- PI + 3 * (PI / 2)) with (PI / 2). - replace (- PI + x) with (x - PI). + replace (- PI + PI / 2) with (- (PI / 2)) by field. + replace (- PI + y) with (y - PI) by apply Rplus_comm. + replace (- PI + 3 * (PI / 2)) with (PI / 2) by field. + replace (- PI + x) with (x - PI) by apply Rplus_comm. intros; apply Ropp_lt_cancel; repeat rewrite <- sin_neg; - replace (- (PI - x)) with (x - PI). - replace (- (PI - y)) with (y - PI). + replace (- (PI - x)) with (x - PI) by ring. + replace (- (PI - y)) with (y - PI) by ring. apply (sin_increasing_1 (x - PI) (y - PI) H7 H8 H5 H6 H4). - unfold Rminus in |- *; rewrite Ropp_plus_distr. - rewrite Ropp_involutive. - apply Rplus_comm. - unfold Rminus in |- *; rewrite Ropp_plus_distr. - rewrite Ropp_involutive. - apply Rplus_comm. - unfold Rminus in |- *; apply Rplus_comm. - pattern PI at 2 in |- *; rewrite double_var; ring. - unfold Rminus in |- *; apply Rplus_comm. - pattern PI at 2 in |- *; rewrite double_var; ring. Qed. Lemma cos_increasing_0 : @@ -1260,44 +1179,22 @@ Proof. intros x y H1 H2 H3 H4; rewrite <- (cos_neg x); rewrite <- (cos_neg y); rewrite <- (cos_period (- x) 1); rewrite <- (cos_period (- y) 1); unfold INR in |- *; - replace (- x + 2 * 1 * PI) with (PI / 2 - (x - 3 * (PI / 2))). - replace (- y + 2 * 1 * PI) with (PI / 2 - (y - 3 * (PI / 2))). + replace (- x + 2 * 1 * PI) with (PI / 2 - (x - 3 * (PI / 2))) by field. + replace (- y + 2 * 1 * PI) with (PI / 2 - (y - 3 * (PI / 2))) by field. repeat rewrite cos_shift; intro H5; generalize (Rplus_le_compat_l (-3 * (PI / 2)) PI x H1); generalize (Rplus_le_compat_l (-3 * (PI / 2)) x (2 * PI) H2); generalize (Rplus_le_compat_l (-3 * (PI / 2)) PI y H3); generalize (Rplus_le_compat_l (-3 * (PI / 2)) y (2 * PI) H4). - replace (-3 * (PI / 2) + y) with (y - 3 * (PI / 2)). - replace (-3 * (PI / 2) + x) with (x - 3 * (PI / 2)). - replace (-3 * (PI / 2) + 2 * PI) with (PI / 2). - replace (-3 * (PI / 2) + PI) with (- (PI / 2)). + replace (-3 * (PI / 2) + y) with (y - 3 * (PI / 2)) by ring. + replace (-3 * (PI / 2) + x) with (x - 3 * (PI / 2)) by ring. + replace (-3 * (PI / 2) + 2 * PI) with (PI / 2) by field. + replace (-3 * (PI / 2) + PI) with (- (PI / 2)) by field. clear H1 H2 H3 H4; intros H1 H2 H3 H4; apply Rplus_lt_reg_l with (-3 * (PI / 2)); - replace (-3 * (PI / 2) + x) with (x - 3 * (PI / 2)). - replace (-3 * (PI / 2) + y) with (y - 3 * (PI / 2)). + replace (-3 * (PI / 2) + x) with (x - 3 * (PI / 2)) by ring. + replace (-3 * (PI / 2) + y) with (y - 3 * (PI / 2)) by ring. apply (sin_increasing_0 (x - 3 * (PI / 2)) (y - 3 * (PI / 2)) H4 H3 H2 H1 H5). - unfold Rminus in |- *. - rewrite Ropp_mult_distr_l_reverse. - apply Rplus_comm. - unfold Rminus in |- *. - rewrite Ropp_mult_distr_l_reverse. - apply Rplus_comm. - pattern PI at 3 in |- *; rewrite double_var. - ring. - rewrite double; pattern PI at 3 4 in |- *; rewrite double_var. - ring. - unfold Rminus in |- *. - rewrite Ropp_mult_distr_l_reverse. - apply Rplus_comm. - unfold Rminus in |- *. - rewrite Ropp_mult_distr_l_reverse. - apply Rplus_comm. - rewrite Rmult_1_r. - rewrite (double PI); pattern PI at 3 4 in |- *; rewrite double_var. - ring. - rewrite Rmult_1_r. - rewrite (double PI); pattern PI at 3 4 in |- *; rewrite double_var. - ring. Qed. Lemma cos_increasing_1 : @@ -1312,31 +1209,16 @@ Proof. generalize (Rplus_lt_compat_l (-3 * (PI / 2)) x y H5); rewrite <- (cos_neg x); rewrite <- (cos_neg y); rewrite <- (cos_period (- x) 1); rewrite <- (cos_period (- y) 1); - unfold INR in |- *; replace (-3 * (PI / 2) + x) with (x - 3 * (PI / 2)). - replace (-3 * (PI / 2) + y) with (y - 3 * (PI / 2)). - replace (-3 * (PI / 2) + PI) with (- (PI / 2)). - replace (-3 * (PI / 2) + 2 * PI) with (PI / 2). + unfold INR in |- *; replace (-3 * (PI / 2) + x) with (x - 3 * (PI / 2)) by ring. + replace (-3 * (PI / 2) + y) with (y - 3 * (PI / 2)) by ring. + replace (-3 * (PI / 2) + PI) with (- (PI / 2)) by field. + replace (-3 * (PI / 2) + 2 * PI) with (PI / 2) by field. clear H1 H2 H3 H4 H5; intros H1 H2 H3 H4 H5; - replace (- x + 2 * 1 * PI) with (PI / 2 - (x - 3 * (PI / 2))). - replace (- y + 2 * 1 * PI) with (PI / 2 - (y - 3 * (PI / 2))). + replace (- x + 2 * 1 * PI) with (PI / 2 - (x - 3 * (PI / 2))) by field. + replace (- y + 2 * 1 * PI) with (PI / 2 - (y - 3 * (PI / 2))) by field. repeat rewrite cos_shift; apply (sin_increasing_1 (x - 3 * (PI / 2)) (y - 3 * (PI / 2)) H5 H4 H3 H2 H1). - rewrite Rmult_1_r. - rewrite (double PI); pattern PI at 3 4 in |- *; rewrite double_var. - ring. - rewrite Rmult_1_r. - rewrite (double PI); pattern PI at 3 4 in |- *; rewrite double_var. - ring. - rewrite (double PI); pattern PI at 3 4 in |- *; rewrite double_var. - ring. - pattern PI at 3 in |- *; rewrite double_var; ring. - unfold Rminus in |- *. - rewrite <- Ropp_mult_distr_l_reverse. - apply Rplus_comm. - unfold Rminus in |- *. - rewrite <- Ropp_mult_distr_l_reverse. - apply Rplus_comm. Qed. Lemma cos_decreasing_0 : @@ -1375,31 +1257,8 @@ Lemma tan_diff : cos x <> 0 -> cos y <> 0 -> tan x - tan y = sin (x - y) / (cos x * cos y). Proof. intros; unfold tan in |- *; rewrite sin_minus. - unfold Rdiv in |- *. - unfold Rminus in |- *. - rewrite Rmult_plus_distr_r. - rewrite Rinv_mult_distr. - repeat rewrite (Rmult_comm (sin x)). - repeat rewrite Rmult_assoc. - rewrite (Rmult_comm (cos y)). - repeat rewrite Rmult_assoc. - rewrite <- Rinv_l_sym. - rewrite Rmult_1_r. - rewrite (Rmult_comm (sin x)). - apply Rplus_eq_compat_l. - rewrite <- Ropp_mult_distr_l_reverse. - rewrite <- Ropp_mult_distr_r_reverse. - rewrite (Rmult_comm (/ cos x)). - repeat rewrite Rmult_assoc. - rewrite (Rmult_comm (cos x)). - repeat rewrite Rmult_assoc. - rewrite <- Rinv_l_sym. - rewrite Rmult_1_r. - reflexivity. - assumption. - assumption. - assumption. - assumption. + field. + now split. Qed. Lemma tan_increasing_0 : @@ -1436,10 +1295,9 @@ Proof. intro H11; generalize (Rge_le (- y) (- (PI / 4)) H11); clear H11; intro H11; generalize (Rplus_le_compat (- (PI / 4)) x (- (PI / 4)) (- y) H H11); - generalize (Rplus_le_compat x (PI / 4) (- y) (PI / 4) H0 H10); - replace (x + - y) with (x - y). - replace (PI / 4 + PI / 4) with (PI / 2). - replace (- (PI / 4) + - (PI / 4)) with (- (PI / 2)). + generalize (Rplus_le_compat x (PI / 4) (- y) (PI / 4) H0 H10). + replace (PI / 4 + PI / 4) with (PI / 2) by field. + replace (- (PI / 4) + - (PI / 4)) with (- (PI / 2)) by field. intros; case (Rtotal_order 0 (x - y)); intro H14. generalize (sin_gt_0 (x - y) H14 (Rle_lt_trans (x - y) (PI / 2) PI H12 PI2_Rlt_PI)); @@ -1447,28 +1305,6 @@ Proof. elim H14; intro H15. rewrite <- H15 in H9; rewrite sin_0 in H9; elim (Rlt_irrefl 0 H9). apply Rminus_lt; assumption. - pattern PI at 1 in |- *; rewrite double_var. - unfold Rdiv in |- *. - rewrite Rmult_plus_distr_r. - repeat rewrite Rmult_assoc. - rewrite <- Rinv_mult_distr. - rewrite Ropp_plus_distr. - replace 4 with 4. - reflexivity. - ring. - discrR. - discrR. - pattern PI at 1 in |- *; rewrite double_var. - unfold Rdiv in |- *. - rewrite Rmult_plus_distr_r. - repeat rewrite Rmult_assoc. - rewrite <- Rinv_mult_distr. - replace 4 with 4. - reflexivity. - ring. - discrR. - discrR. - reflexivity. case (Rcase_abs (sin (x - y))); intro H9. assumption. generalize (Rge_le (sin (x - y)) 0 H9); clear H9; intro H9; @@ -1482,8 +1318,7 @@ Proof. (Rlt_le 0 (/ (cos x * cos y)) H12)); intro H13; elim (Rlt_irrefl 0 (Rle_lt_trans 0 (sin (x - y) * / (cos x * cos y)) 0 H13 H3)). - rewrite Rinv_mult_distr. - reflexivity. + apply Rinv_mult_distr. assumption. assumption. Qed. @@ -1521,9 +1356,8 @@ Proof. clear H10 H11; intro H8; generalize (Ropp_le_ge_contravar y (PI / 4) H2); intro H11; generalize (Rge_le (- y) (- (PI / 4)) H11); clear H11; intro H11; - generalize (Rplus_le_compat (- (PI / 4)) x (- (PI / 4)) (- y) H H11); - replace (x + - y) with (x - y). - replace (- (PI / 4) + - (PI / 4)) with (- (PI / 2)). + generalize (Rplus_le_compat (- (PI / 4)) x (- (PI / 4)) (- y) H H11). + replace (- (PI / 4) + - (PI / 4)) with (- (PI / 2)) by field. clear H11; intro H9; generalize (Rlt_minus x y H3); clear H3; intro H3; clear H H0 H1 H2 H4 H5 HP1 HP2; generalize PI2_Rlt_PI; intro H1; generalize (Ropp_lt_gt_contravar (PI / 2) PI H1); @@ -1534,18 +1368,6 @@ Proof. generalize (Rmult_lt_gt_compat_neg_l (sin (x - y)) 0 (/ (cos x * cos y)) H2 H8); rewrite Rmult_0_r; intro H4; assumption. - pattern PI at 1 in |- *; rewrite double_var. - unfold Rdiv in |- *. - rewrite Rmult_plus_distr_r. - repeat rewrite Rmult_assoc. - rewrite <- Rinv_mult_distr. - replace 4 with 4. - rewrite Ropp_plus_distr. - reflexivity. - ring. - discrR. - discrR. - reflexivity. apply Rinv_mult_distr; assumption. Qed. @@ -1737,7 +1559,7 @@ Proof. rewrite H5. rewrite mult_INR. simpl in |- *. - rewrite <- (Rplus_0_l (2 * INR x2 * PI)). + rewrite <- (Rplus_0_l ((1 + 1) * INR x2 * PI)). rewrite sin_period. apply sin_0. rewrite H5. @@ -1747,7 +1569,7 @@ Proof. rewrite Rmult_1_l; rewrite sin_plus. rewrite sin_PI. rewrite Rmult_0_r. - rewrite <- (Rplus_0_l (2 * INR x2 * PI)). + rewrite <- (Rplus_0_l ((1 + 1) * INR x2 * PI)). rewrite sin_period. rewrite sin_0; ring. apply le_IZR. @@ -1769,7 +1591,7 @@ Proof. rewrite H5. rewrite mult_INR. simpl in |- *. - rewrite <- (Rplus_0_l (2 * INR x2 * PI)). + rewrite <- (Rplus_0_l ((1 + 1) * INR x2 * PI)). rewrite sin_period. rewrite sin_0; ring. rewrite H5. @@ -1779,7 +1601,7 @@ Proof. rewrite Rmult_1_l; rewrite sin_plus. rewrite sin_PI. rewrite Rmult_0_r. - rewrite <- (Rplus_0_l (2 * INR x2 * PI)). + rewrite <- (Rplus_0_l ((1 + 1) * INR x2 * PI)). rewrite sin_period. rewrite sin_0; ring. apply le_IZR. @@ -1787,8 +1609,7 @@ Proof. rewrite Rplus_0_r. rewrite Ropp_Ropp_IZR. rewrite Rplus_opp_r. - left; replace 0 with (IZR 0); [ apply IZR_lt | reflexivity ]. - assumption. + now apply Rlt_le, IZR_lt. rewrite <- sin_neg. rewrite Ropp_mult_distr_l_reverse. rewrite Ropp_involutive. @@ -1858,7 +1679,7 @@ Proof. - right; left; auto. - left. clear Hi. subst. - replace 0 with (IZR 0 * PI) by (simpl; ring). f_equal. f_equal. + replace 0 with (IZR 0 * PI) by apply Rmult_0_l. f_equal. f_equal. apply one_IZR_lt1. split. + apply Rlt_le_trans with 0; |