Uniform Convergence of sequence

In summary, the conversation is discussing the uniform convergence of the sequence {x^n} in the interval 0 < x < 1. It is stated that if f(x) is the limit of the sequence and for any small epsilon, there exists a value of N such that the difference between f_n(x) and f(x) is less than epsilon for all n greater than or equal to N, then f_n(x) is uniformly convergent. However, it is not possible to find a fixed N that satisfies this condition for all values of n and x in the given interval. Therefore, it is concluded that x^n is not uniformly convergent. Additionally, the person asking the question is seeking confirmation that their reasoning is correct and clar
  • #1
siddharth
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Discuss the uniform convergence of the following sequence in the interval indicated

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

Now,
[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?
 
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  • #2
xn is convergent, just not uniformly convergent. Does that make sense?
 
  • #3
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FAQ: Uniform Convergence of sequence

What is uniform convergence of a sequence?

Uniform convergence of a sequence is a mathematical concept that refers to the behavior of a sequence of functions. It means that a sequence of functions converges to a limit function in such a way that the rate of convergence is the same at every point in the domain.

What is the difference between pointwise convergence and uniform convergence?

The difference between pointwise convergence and uniform convergence lies in the way the limit function is approached. In pointwise convergence, the rate of convergence may vary at different points in the domain, while in uniform convergence, the rate of convergence remains the same at every point.

How is uniform convergence of a sequence determined?

The uniform convergence of a sequence can be determined by checking if the sequence of functions satisfies the Cauchy criterion. This means that for any given epsilon, there exists an N such that for all n and m greater than or equal to N, the difference between the two functions is less than epsilon at every point in the domain.

What are the applications of uniform convergence of a sequence?

Uniform convergence of a sequence has many applications in mathematics, physics, and engineering. It is used in the study of Fourier series, power series, and Taylor series. It also plays a crucial role in the convergence of numerical methods and the analysis of differential equations.

Can a sequence of continuous functions uniformly converge to a discontinuous function?

No, a sequence of continuous functions cannot uniformly converge to a discontinuous function. This is because the limit function of a uniformly convergent sequence must also be continuous. If the limit function is discontinuous, then the sequence is not uniformly convergent.

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