Need to show that a limit exists

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In summary, the problem asks to prove that if a sequence of functions uniformly converges to a function, and each function in the sequence approaches 0 as x approaches infinity, then the limit of the sequence also approaches 0 as x approaches infinity. This can be shown using the definition of limits at infinity and the fact that uniform convergence implies pointwise convergence.
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Demon117
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Homework Statement


Suppose that [tex]f_{n}[/tex]:R[tex]\rightarrow[/tex]R convergy uniformly to f. If each function [tex]f_{n}[/tex] satisfies [tex]f_{n}[/tex][tex]\rightarrow[/tex] 0 as x[tex]\rightarrow[/tex][tex]\infty[/tex], prove that f[tex]\rightarrow[/tex]0 as x[tex]\rightarrow[/tex][tex]\infty[/tex]. That is show that the limit exists.


Homework Equations


Definition of uniform convergense
Uniform convergence implies pointwise convergence
definition of limits at infinity


The Attempt at a Solution



I have tried to make an estimation using the definition of limits at infinity. I have no idea what I am doing incorrectly but I keep getting that |f(x)|<0 for some reason.

Any advice on this one?
 
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  • #2
matumich26 said:

Homework Statement


Suppose that [tex]f_{n}[/tex]:R[tex]\rightarrow[/tex]R convergy uniformly to f. If each function [tex]f_{n}[/tex] satisfies [tex]f_{n}[/tex][tex]\rightarrow[/tex] 0 as x[tex]\rightarrow[/tex][tex]\infty[/tex], prove that f[tex]\rightarrow[/tex]0 as x[tex]\rightarrow[/tex][tex]\infty[/tex]. That is show that the limit exists.

Also, why is my latex so screwed up?
 

1. What is a limit in mathematics?

A limit in mathematics is a fundamental concept that describes the behavior of a function as its input approaches a specific value. It represents the value that a function is approaching, rather than the actual value it reaches at that point.

2. Why do we need to show that a limit exists?

Showing that a limit exists is important because it allows us to understand the behavior of a function near a specific point. It also helps us determine the continuity and differentiability of a function at that point.

3. How do we show that a limit exists?

The most common method to show that a limit exists is by using the epsilon-delta definition. This involves choosing a small value for epsilon (ε) and finding a corresponding value for delta (δ) that ensures that the function's output will be within ε of the limit as the input approaches the chosen value.

4. Can a limit exist even if the function is not defined at the point?

Yes, a limit can exist even if the function is not defined at the specific point. This is because a limit only describes the behavior of the function as the input approaches the point, not the actual value at that point.

5. What are some common ways to prove that a limit exists?

In addition to using the epsilon-delta definition, other common ways to prove that a limit exists include using the Squeeze Theorem, the Intermediate Value Theorem, and L'Hôpital's Rule. These methods may be more efficient for certain functions and can be used as alternative approaches to showing the existence of a limit.

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