Prove this statement (limits and sequences)

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In summary, the problem involves finding the limit of a function f(x) as x approaches infinity and a sequence xn as n approaches infinity. The task is to prove, using definitions, that the limit of f(xn) is equal to a.
  • #1
lep11
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Homework Statement


Let lim f(x)=a as x appr. infinity
Let xn be a sequence so that lim xn=infinity as n appr. infinity. Prove using definitions that then lim f(xn)=a as n appr. infinity.

Homework Equations


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The Attempt at a Solution


I have had hard time trying to grasp how to begin with this...

Because lim f(x)=a as x appr. infinity there
 
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  • #2
lep11 said:
Because lim f(x)=a as x appr. infinity there
And that is good otherwise the statement would be wrong.

I would try to use the elementary definitions of convergence for the function and the sequence.
 

FAQ: Prove this statement (limits and sequences)

What is the definition of a limit?

A limit is the value that a function or sequence approaches as the input or index approaches a certain value. It represents the behavior of the function or sequence near a specific point.

How do you prove a limit using the epsilon-delta definition?

To prove a limit using the epsilon-delta definition, you must show that for every positive epsilon (ε), there exists a corresponding positive delta (δ) such that if the distance between the input and the limit point is less than delta, then the distance between the output and the limit is less than epsilon.

What is the squeeze theorem and how is it used to prove limits?

The squeeze theorem, also known as the sandwich theorem, states that if two functions have the same limit as x approaches a certain value, and a third function is always between them, then the third function also has the same limit at that point. This can be used to prove limits by finding two functions that are easier to evaluate and using them to bound the function in question.

Can a sequence have multiple limits?

No, a sequence can only have one limit. If a sequence has multiple limits, then it is considered divergent and does not have a limit.

How is the concept of a limit used in real-world applications?

Limits are used in many real-world applications, including in physics, economics, and engineering. In physics, limits are used to calculate instantaneous rates of change, such as velocity and acceleration. In economics, limits are used to model supply and demand curves. In engineering, limits are used to optimize designs and analyze the behavior of systems.

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