What is the Limit of f(x) as x Approaches Infinity?

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Homework Help Overview

The discussion revolves around determining the limit of the function f(x) = [xsinx] / [x^2 + 1] as x approaches infinity. Participants are exploring whether a limit exists and what that limit might be.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants are considering the behavior of the sine function and its impact on the limit as x approaches infinity. There is discussion about the form of the limit being an indeterminate type (infinity over infinity) and the implications of this for finding the limit.

Discussion Status

The conversation is ongoing, with participants offering different perspectives on the behavior of the function as x increases. Some have suggested methods for simplifying the expression, while others are questioning the assumptions about the sine function's behavior at infinity.

Contextual Notes

There is a recognition of the cyclical nature of the sine function and its bounded range, which is being considered in the context of the limit. Participants are also navigating the implications of dividing by terms that approach infinity.

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Homework Statement



For the following function decide whether f(x) tends to a limit as x tends to infinity. When the limit exists find it.


Homework Equations



f(x)=[xsinx] / [x^2 +1]

The Attempt at a Solution



Im not really sure what method to use for this question.
 
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well sinx cycles from -1 to 1, to infinity and x tends to infinity. What happens to:

x^2+1\;\lim_{x\rightarrow\infty}
 
Last edited:


x^2 + 1 tends to infinity as x tends to infinity. So infinity over infinity?
 


Actually not exactly as sinx goes from -1 to 1 to the limit of infinity and x goes to infinity so it's between - 1 x infinity and 1 x infinity, infinitely as x approaches infinity. Hehe that makes sense. :smile:
 
Last edited:


As to my methodology,

<br /> \lim_{x\rightarrow\infty}\frac{xsinx}{x^2+1}

Taking x^2 common, we have the above equation as,
\lim_{x\rightarrow\infty}\frac{x^2(\frac{sinx}{x})}{x^2(1+\frac{1}{x^2})}

Now, cancelling x^2 terms and also we know that \frac{1}{\infty}=~0,

Thus, the function tends to?
(It can't get easier than this.. c'mon..)
 

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