Find the mistake in the following “proof": "Statement". If fn : X → Y is a sequence of functions converging uniformly on X to a function f, and if f is continuous at xo, then there exists N e N such that fn is continuous at xo for all n > N. "Proof". Let ɛ > 0. By uniform convergence, we can find N e N such that Vn > N, Vx E X : dy (fn(x), f (x)) < By continuity of f at xo, we furthermore find 8 > 0 such that Vx € X : dx(x, xo) < 8 → dy(f(x), f(xo)) < Hence whenever n > N and dx(x,xo) < & we get dy(fn(x), fn(xo)) < dy(fn(x), f(x)) + dy(f(x), f(xo)) + dy (f(xo), fn(x0)) = E. Hence fn is continuous at xo for all n >N.

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question

Uniform converg

Find the mistake in the following "proof":
"Statement". If fn : X → Y is a sequence of functions converging uniformly on X to a
function f, and if f is continuous at xo, then there exists N E N such that fn is continuous
at xo for all n > N.
"Proof". Let ɛ > 0. By uniform convergence, we can find N EN such that
Vn > N, Væ e X : dy(fn(x), f(x)) <
3
By continuity of f at xo, we furthermore find 8 > 0 such that
Vx E X : dx(x, xo) < 8 → dy(f (x), f(xo)) <
6.
Hence whenever n > N and dx(x, xo) < 8 we get
dy (fn(x), fn(x0)) < dy(fn(x), f(x)) + dy (f(x), f(xo)) + dy (f (x0), fn(x0))
3
3
= E.
Hence fn is continuous at xo for all n >N.
Transcribed Image Text:Find the mistake in the following "proof": "Statement". If fn : X → Y is a sequence of functions converging uniformly on X to a function f, and if f is continuous at xo, then there exists N E N such that fn is continuous at xo for all n > N. "Proof". Let ɛ > 0. By uniform convergence, we can find N EN such that Vn > N, Væ e X : dy(fn(x), f(x)) < 3 By continuity of f at xo, we furthermore find 8 > 0 such that Vx E X : dx(x, xo) < 8 → dy(f (x), f(xo)) < 6. Hence whenever n > N and dx(x, xo) < 8 we get dy (fn(x), fn(x0)) < dy(fn(x), f(x)) + dy (f(x), f(xo)) + dy (f (x0), fn(x0)) 3 3 = E. Hence fn is continuous at xo for all n >N.
Expert Solution
steps

Step by step

Solved in 4 steps

Blurred answer
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,