2. Assume that for x # c (in some open interval containing c), I(x) < f(x) < u (x) and that lim 1(x) = lim u(x) = L. Then lim f(x) exists and lim f(x) = L

Calculus: Early Transcendentals
8th Edition
ISBN:9781285741550
Author:James Stewart
Publisher:James Stewart
Chapter1: Functions And Models
Section: Chapter Questions
Problem 1RCC: (a) What is a function? What are its domain and range? (b) What is the graph of a function? (c) How...
icon
Related questions
Question
2. Assume that for x # c (in some open interval containing c),
I(x) < f(x) < u (x)
and that lim 1(x) = lim u(x) = L. Then lim f(x) exists and
lim f(x) = L
Transcribed Image Text:2. Assume that for x # c (in some open interval containing c), I(x) < f(x) < u (x) and that lim 1(x) = lim u(x) = L. Then lim f(x) exists and lim f(x) = L
Expert Solution
Step 1 Given

lx fxux

and that limxc lx =limxc ux =L

Now to show that limxc fx  exists and limxc fx =L 

Here use definition of limit 

Let ε >0 be given. We are done if we find a δ >0 such that 

fx-L<ε  whenever 0 <x-c<δ .

Since limxc lx =L, by definition of limits, there exits some δ1 >0 such that

lx-L<ε  for all 0 <x-c<δ1.

Thus , 

          -ε <lx-L<ε  for all 0<x-c<δ1,

So we get 

   L-ε <lx<L+ε  for all 0<x-c<δ1.   ----------(1)

Similarly , since limxc ux =L, by definition of limits, there exits some δ2 >0 such that

L-ε <ux <L+ε   for all 0<x-c<δ2       -----------(2)

steps

Step by step

Solved in 2 steps

Blurred answer
Recommended textbooks for you
Calculus: Early Transcendentals
Calculus: Early Transcendentals
Calculus
ISBN:
9781285741550
Author:
James Stewart
Publisher:
Cengage Learning
Thomas' Calculus (14th Edition)
Thomas' Calculus (14th Edition)
Calculus
ISBN:
9780134438986
Author:
Joel R. Hass, Christopher E. Heil, Maurice D. Weir
Publisher:
PEARSON
Calculus: Early Transcendentals (3rd Edition)
Calculus: Early Transcendentals (3rd Edition)
Calculus
ISBN:
9780134763644
Author:
William L. Briggs, Lyle Cochran, Bernard Gillett, Eric Schulz
Publisher:
PEARSON
Calculus: Early Transcendentals
Calculus: Early Transcendentals
Calculus
ISBN:
9781319050740
Author:
Jon Rogawski, Colin Adams, Robert Franzosa
Publisher:
W. H. Freeman
Precalculus
Precalculus
Calculus
ISBN:
9780135189405
Author:
Michael Sullivan
Publisher:
PEARSON
Calculus: Early Transcendental Functions
Calculus: Early Transcendental Functions
Calculus
ISBN:
9781337552516
Author:
Ron Larson, Bruce H. Edwards
Publisher:
Cengage Learning