diff options
author | desmettr <desmettr@85f007b7-540e-0410-9357-904b9bb8a0f7> | 2003-01-21 16:45:48 +0000 |
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committer | desmettr <desmettr@85f007b7-540e-0410-9357-904b9bb8a0f7> | 2003-01-21 16:45:48 +0000 |
commit | 37e7da6a31dc353db67ec18938df89b07ff9e17f (patch) | |
tree | 22200b9f502044a044225eb31c2b2a5b6b44955d /theories/Reals/MVT.v | |
parent | 1a121610f8bc6761fea9dd4c41ed5255e37db657 (diff) |
Renommage dans MVT
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@3564 85f007b7-540e-0410-9357-904b9bb8a0f7
Diffstat (limited to 'theories/Reals/MVT.v')
-rw-r--r-- | theories/Reals/MVT.v | 36 |
1 files changed, 17 insertions, 19 deletions
diff --git a/theories/Reals/MVT.v b/theories/Reals/MVT.v index d797bb7d5..b271d408b 100644 --- a/theories/Reals/MVT.v +++ b/theories/Reals/MVT.v @@ -13,8 +13,8 @@ Require Rfunctions. Require Ranalysis1. Require Rtopology. -(* Théorème des accroissements finis généralisés *) -Theorem TAF_gen : (f,g:R->R;a,b:R;pr1:(c:R)``a<c<b``->(derivable_pt f c);pr2:(c:R)``a<c<b``->(derivable_pt g c)) ``a<b`` -> ((c:R)``a<=c<=b``->(continuity_pt f c)) -> ((c:R)``a<=c<=b``->(continuity_pt g c)) -> (EXT c : R | (EXT P : ``a<c<b`` | ``((g b)-(g a))*(derive_pt f c (pr1 c P))==((f b)-(f a))*(derive_pt g c (pr2 c P))``)). +(* The Mean Value Theorem *) +Theorem MVT : (f,g:R->R;a,b:R;pr1:(c:R)``a<c<b``->(derivable_pt f c);pr2:(c:R)``a<c<b``->(derivable_pt g c)) ``a<b`` -> ((c:R)``a<=c<=b``->(continuity_pt f c)) -> ((c:R)``a<=c<=b``->(continuity_pt g c)) -> (EXT c : R | (EXT P : ``a<c<b`` | ``((g b)-(g a))*(derive_pt f c (pr1 c P))==((f b)-(f a))*(derive_pt g c (pr2 c P))``)). Intros; Assert H2 := (Rlt_le ? ? H). Pose h := [y:R]``((g b)-(g a))*(f y)-((f b)-(f a))*(g y)``. Cut (c:R)``a<c<b``->(derivable_pt h c). @@ -104,13 +104,13 @@ Apply derivable_pt_const. Apply (pr2 ? H3). Qed. -(* Une version plus faible (mais usuelle ) *) -Lemma TAF : (f:(R->R); a,b:R; pr:(derivable f)) ``a < b``->(EXT c:R | ``(f b)-(f a) == (derive_pt f c (pr c))*(b-a)``/\``a < c < b``). +(* Corollaries ... *) +Lemma MVT_cor1 : (f:(R->R); a,b:R; pr:(derivable f)) ``a < b``->(EXT c:R | ``(f b)-(f a) == (derive_pt f c (pr c))*(b-a)``/\``a < c < b``). Intros; Cut (c:R)``a<c<b``->(derivable_pt f c); [Intro | Intros; Apply pr]. Cut (c:R)``a<c<b``->(derivable_pt id c); [Intro | Intros; Apply derivable_pt_id]. Cut ((c:R)``a<=c<=b``->(continuity_pt f c)); [Intro | Intros; Apply derivable_continuous_pt; Apply pr]. Cut ((c:R)``a<=c<=b``->(continuity_pt id c)); [Intro | Intros; Apply derivable_continuous_pt; Apply derivable_id]. -Assert H2 := (TAF_gen f id a b X X0 H H0 H1). +Assert H2 := (MVT f id a b X X0 H H0 H1). Elim H2; Intros c H3; Elim H3; Intros. Exists c; Split. Cut (derive_pt id c (X0 c x)) == (derive_pt id c (derivable_pt_id c)); [Intro | Apply pr_nu]. @@ -118,14 +118,14 @@ Rewrite H5 in H4; Rewrite (derive_pt_id c) in H4; Rewrite Rmult_1r in H4; Rewrit Apply x. Qed. -Theorem TAF_cor1 : (f,f':R->R;a,b:R) ``a<b`` -> ((c:R)``a<=c<=b``->(derivable_pt_lim f c (f' c))) -> (EXT c:R | ``(f b)-(f a)==(f' c)*(b-a)``/\``a<c<b``). +Theorem MVT_cor2 : (f,f':R->R;a,b:R) ``a<b`` -> ((c:R)``a<=c<=b``->(derivable_pt_lim f c (f' c))) -> (EXT c:R | ``(f b)-(f a)==(f' c)*(b-a)``/\``a<c<b``). Intros; Cut ((c:R)``a<=c<=b``->(derivable_pt f c)). Intro; Cut ((c:R)``a<c<b``->(derivable_pt f c)). Intro; Cut ((c:R)``a<=c<=b``->(continuity_pt f c)). Intro; Cut ((c:R)``a<=c<=b``->(derivable_pt id c)). Intro; Cut ((c:R)``a<c<b``->(derivable_pt id c)). Intro; Cut ((c:R)``a<=c<=b``->(continuity_pt id c)). -Intro; Elim (TAF_gen f id a b X0 X2 H H1 H2); Intros; Elim H3; Clear H3; Intros; Exists x; Split. +Intro; Elim (MVT f id a b X0 X2 H H1 H2); Intros; Elim H3; Clear H3; Intros; Exists x; Split. Cut (derive_pt id x (X2 x x0))==R1. Cut (derive_pt f x (X0 x x0))==(f' x). Intros; Rewrite H4 in H3; Rewrite H5 in H3; Unfold id in H3; Rewrite Rmult_1r in H3; Rewrite Rmult_sym; Symmetry; Assumption. @@ -140,16 +140,14 @@ Intros; Elim H1; Intros; Apply X; Split; Left; Assumption. Intros; Unfold derivable_pt; Apply Specif.existT with (f' c); Apply H0; Apply H1. Qed. -Lemma TAF_cor2 : (f,f':(R->R); a,b:R) ``a < b`` -> ((x:R)``a <= x`` -> ``x <= b``->(derivable_pt_lim f x (f' x))) -> (EXT c:R | ``a<=c``/\``c<=b``/\``(f b)==(f a) + (f' c)*(b-a)``). -Intros; Assert H1 : (EXT c:R | ``(f b) -(f a) == (f' c)*(b-a)``/\``a<c<b``); [Apply TAF_cor1; [Apply H | Intros; Elim H1; Intros; Apply (H0 ? H2 H3)] | Elim H1; Intros; Exists x; Elim H2; Intros; Elim H4; Intros; Split; [Left; Assumption | Split; [Left; Assumption | Rewrite <- H3; Ring]]]. +Lemma MVT_cor3 : (f,f':(R->R); a,b:R) ``a < b`` -> ((x:R)``a <= x`` -> ``x <= b``->(derivable_pt_lim f x (f' x))) -> (EXT c:R | ``a<=c``/\``c<=b``/\``(f b)==(f a) + (f' c)*(b-a)``). +Intros; Assert H1 : (EXT c:R | ``(f b) -(f a) == (f' c)*(b-a)``/\``a<c<b``); [Apply MVT_cor2; [Apply H | Intros; Elim H1; Intros; Apply (H0 ? H2 H3)] | Elim H1; Intros; Exists x; Elim H2; Intros; Elim H4; Intros; Split; [Left; Assumption | Split; [Left; Assumption | Rewrite <- H3; Ring]]]. Qed. -(*** Corollaires ***) - Lemma Rolle : (f:R->R;a,b:R;pr:(x:R)``a<x<b``->(derivable_pt f x)) ((x:R)``a<=x<=b``->(continuity_pt f x)) -> ``a<b`` -> (f a)==(f b) -> (EXT c:R | (EXT P: ``a<c<b`` | ``(derive_pt f c (pr c P))==0``)). Intros; Assert H2 : (x:R)``a<x<b``->(derivable_pt id x). Intros; Apply derivable_pt_id. -Assert H3 := (TAF_gen f id a b pr H2 H0 H); Assert H4 : (x:R)``a<=x<=b``->(continuity_pt id x). +Assert H3 := (MVT f id a b pr H2 H0 H); Assert H4 : (x:R)``a<=x<=b``->(continuity_pt id x). Intros; Apply derivable_continuous; Apply derivable_id. Elim (H3 H4); Intros; Elim H5; Intros; Exists x; Exists x0; Rewrite H1 in H6; Unfold id in H6; Unfold Rminus in H6; Rewrite Rplus_Ropp_r in H6; Rewrite Rmult_Ol in H6; Apply r_Rmult_mult with ``b-a``; [Rewrite Rmult_Or; Apply H6 | Apply Rminus_eq_contra; Red; Intro; Rewrite H7 in H0; Elim (Rlt_antirefl ? H0)]. Qed. @@ -163,7 +161,7 @@ Case (total_order_T x y); Intro. Elim s; Intro. Apply Rle_anti_compatibility with ``-(f x)``. Rewrite Rplus_Ropp_l; Rewrite Rplus_sym. -Assert H1 := (TAF f ? ? pr a). +Assert H1 := (MVT_cor1 f ? ? pr a). Elim H1; Intros. Elim H2; Intros. Unfold Rminus in H3. @@ -294,7 +292,7 @@ Unfold strict_increasing. Intros. Apply Rlt_anti_compatibility with ``-(f x)``. Rewrite Rplus_Ropp_l; Rewrite Rplus_sym. -Assert H1 := (TAF f ? ? pr H0). +Assert H1 := (MVT_cor1 f ? ? pr H0). Elim H1; Intros. Elim H2; Intros. Unfold Rminus in H3. @@ -371,7 +369,7 @@ Intros. Split; Intros. Apply Rlt_anti_compatibility with ``-(f x)``. Rewrite Rplus_Ropp_l; Rewrite Rplus_sym. -Assert H4 := (TAF f ? ? pr H3). +Assert H4 := (MVT_cor1 f ? ? pr H3). Elim H4; Intros. Elim H5; Intros. Unfold Rminus in H6. @@ -388,7 +386,7 @@ Apply Rlt_anti_compatibility with x. Rewrite Rplus_Or; Replace ``x+(y+ -x)`` with y; [Assumption | Ring]. Apply Rle_anti_compatibility with ``-(f x)``. Rewrite Rplus_Ropp_l; Rewrite Rplus_sym. -Assert H4 := (TAF f ? ? pr H3). +Assert H4 := (MVT_cor1 f ? ? pr H3). Elim H4; Intros. Elim H5; Intros. Unfold Rminus in H6. @@ -423,7 +421,7 @@ Theorem IAF : (f:R->R;a,b,k:R;pr:(derivable f)) ``a<=b`` -> ((c:R) ``a<=c<=b`` - Intros. Case (total_order_T a b); Intro. Elim s; Intro. -Assert H1 := (TAF f ? ? pr a0). +Assert H1 := (MVT_cor1 f ? ? pr a0). Elim H1; Intros. Elim H2; Intros. Rewrite H3. @@ -482,7 +480,7 @@ Intros; Apply H; Elim H5; Intros; Split. Assumption. Elim H1; Intros; Apply Rle_trans with x; Assumption. Elim H1; Clear H1; Intros; Elim H1; Clear H1; Intro. -Assert H7 := (TAF_gen f id a x H4 H2 H1 H5 H3). +Assert H7 := (MVT f id a x H4 H2 H1 H5 H3). Elim H7; Intros; Elim H8; Intros; Assert H10 : ``a<x0<b``. Elim x1; Intros; Split. Assumption. @@ -499,7 +497,7 @@ Rewrite H2; Reflexivity. Elim H1; Intros; Elim (Rlt_antirefl ? (Rle_lt_trans ? ? ? (Rle_trans ? ? ? H2 H3) r)). Qed. -(* La primitive est unique a une constante pres *) +(* Unicity of the antiderivative *) Lemma antiderivative_Ucte : (f,g1,g2:R->R;a,b:R) (antiderivative f g1 a b) -> (antiderivative f g2 a b) -> (EXT c:R | (x:R)``a<=x<=b``->``(g1 x)==(g2 x)+c``). Unfold antiderivative; Intros; Elim H; Clear H; Intros; Elim H0; Clear H0; Intros H0 _; Exists ``(g1 a)-(g2 a)``; Intros; Assert H3 : (x:R)``a<=x<=b``->(derivable_pt g1 x). Intros; Unfold derivable_pt; Apply Specif.existT with (f x0); Elim (H x0 H3); Intros; EApply derive_pt_eq_1; Symmetry; Apply H4. |