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Uniform Convergence of sequence

  1. Oct 10, 2005 #1


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    Discuss the uniform convergence of the following sequence in the interval indicated

    [tex] {x^n} , 0< x <1 [/tex]

    [tex] f(x) = \lim_{n\rightarrow \infty} f_{n}(x) = 0[/tex]
    Therefore given any small [tex] \epsilon > 0 [/tex], if there exists [tex] N [/tex] such that [tex] |f_n(x)-f(x)| < \epsilon [/tex] for all [tex] n \geq N [/tex] for all x in the given interval, then f_n(x) is uniformly convergent.

    That gives

    [tex] x^n < \epsilon [/tex]

    [tex]n > \frac{\log \epsilon }{\log x} [/tex]

    So, it is not possible to fix an [tex] N [/tex] such that the above condition is satisfied for all values of n>N because for a given value of N, I can always find a value of x close to 1 such that the above condition is not valid.
    Hence [tex] x^n [/tex] is not uniformly convergent in the given interval.

    Is my above reasoning correct?
    Last edited: Oct 10, 2005
  2. jcsd
  3. Oct 10, 2005 #2


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    xn is convergent, just not uniformly convergent. Does that make sense?
  4. Oct 10, 2005 #3


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    Yes, it does make sense. The reason I asked this is because I was confused after reading this thread.
    "https://www.physicsforums.com/showthread.php?t=92619" [Broken]
    Last edited by a moderator: Apr 21, 2017 at 8:41 PM
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