diff options
Diffstat (limited to 'theories/Reals/Machin.v')
| -rw-r--r-- | theories/Reals/Machin.v | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/theories/Reals/Machin.v b/theories/Reals/Machin.v index 311f29098..cfb50231c 100644 --- a/theories/Reals/Machin.v +++ b/theories/Reals/Machin.v @@ -28,6 +28,7 @@ Lemma atan_sub_correct : forall u v, 1 + u * v <> 0 -> -PI/2 < atan u - atan v < PI/2 -> -PI/2 < atan (atan_sub u v) < PI/2 -> atan u = atan v + atan (atan_sub u v). +Proof. intros u v pn0 uvint aint. assert (cos (atan u) <> 0). destruct (atan_bound u); apply Rgt_not_eq, cos_gt_0; auto. @@ -45,6 +46,7 @@ Qed. Lemma tech : forall x y , -1 <= x <= 1 -> -1 < y < 1 -> -PI/2 < atan x - atan y < PI/2. +Proof. assert (ut := PI_RGT_0). intros x y [xm1 x1] [ym1 y1]. assert (-(PI/4) <= atan x). @@ -68,6 +70,7 @@ Qed. (* A simple formula, reasonably efficient. *) Lemma Machin_2_3 : PI/4 = atan(/2) + atan(/3). +Proof. assert (utility : 0 < PI/2) by (apply PI2_RGT_0). rewrite <- atan_1. rewrite (atan_sub_correct 1 (/2)). @@ -78,6 +81,7 @@ apply atan_bound. Qed. Lemma Machin_4_5_239 : PI/4 = 4 * atan (/5) - atan(/239). +Proof. rewrite <- atan_1. rewrite (atan_sub_correct 1 (/5)); [ | apply Rgt_not_eq; fourier | apply tech; try split; fourier | @@ -106,6 +110,7 @@ unfold atan_sub; field. Qed. Lemma Machin_2_3_7 : PI/4 = 2 * atan(/3) + (atan (/7)). +Proof. rewrite <- atan_1. rewrite (atan_sub_correct 1 (/3)); [ | apply Rgt_not_eq; fourier | apply tech; try split; fourier | |