Top Banner
The Squeeze Theorem U)(The Squeeze Theorem) Min Eun Gi : https://www.facebook.com/mineungimath
29

U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

Apr 30, 2020

Download

Documents

dariahiddleston
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

압착정리(The Squeeze Theorem)

Min Eun Gi : https://www.facebook.com/mineungimath

Page 2: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theorem

f (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , limx→a

f (x) = limx→a

h(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 3: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 4: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0

s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 5: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t.

0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 6: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1

⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 7: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒

|f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 8: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε

(∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 9: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L)

, L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 10: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 11: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0

s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 12: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t.

0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 13: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2

⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 14: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒

|h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 15: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε

(∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 16: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L)

, L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 17: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 18: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ

= min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 19: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 20: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x)

, L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 21: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε

, L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 22: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε

, |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 23: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 24: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0

s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 25: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.

0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 26: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ

⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 27: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒

|g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 28: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Start

Theoremf (x) ≤ g(x) ≤ h(x)(0 < |x− a| < δ0) , lim

x→af (x) = lim

x→ah(x) = L

limx→a

g(x) = L

Proof.ε > 0

∃δ1 > 0 s.t. 0 < |x− a| < δ1 ⇒ |f (x)− L| < ε (∵ limx→a

f (x) = L) , L− ε < f (x) < L + ε

∃δ2 > 0 s.t. 0 < |x− a| < δ2 ⇒ |h(x)− L| < ε (∵ limx→a

h(x) = L) , L− ε < g(x) < L + ε

δ = min{δ0, δ1, δ2}

f (x) ≤ g(x) ≤ h(x) , L− ε < f (x) ≤ g(x) ≤ h(x) < L + ε , L− ε < g(x) < L + ε , |g(x)− L| < ε

∴ ∀ε > 0 , ∃δ > 0 s.t.0 < |x− a| < δ ⇒ |g(x)− L| < ε

Min Eun Gi : https://www.facebook.com/mineungimath

Page 29: U (The Squeeze Theorem) · The Squeeze Theorem U) ‹ (The Squeeze Theorem) Min Eun Gi :

The Squeeze Theorem

Home

Min Eun Gi : https://www.facebook.com/mineungimath