Limits when there is a sine function?

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Homework Help Overview

The discussion revolves around evaluating the limit as x approaches infinity for the expression xsin(1/x). Participants explore the nature of this limit, which is characterized as an ∞.0 type limit due to the behavior of the sine function as its argument approaches zero.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the transformation of the sine function to facilitate limit evaluation. There are hints regarding the use of L'Hôpital's Rule and connections to a well-known limit involving sine. Questions arise about the implications of these transformations and the appropriate methods to apply.

Discussion Status

The discussion is active, with participants providing hints and exploring different approaches to the limit. There is no explicit consensus on the best method, but several productive directions are being considered, including substitutions and references to established limits.

Contextual Notes

Participants are navigating the constraints of the limit's form and the behavior of the sine function as its argument approaches zero. There is an emphasis on understanding the implications of these mathematical relationships without reaching a definitive conclusion.

applestrudle
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Homework Statement



lim x-> ∞ xsin(1/x)

Homework Equations


The Attempt at a Solution



I know that this is an ∞.0 type limit but I can't figure out how to change the sin function.

Thank you
 
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Hint
[tex]x \sin(1/x)=\frac{\sin(1/x)}{1/x}.[/tex]
 
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vanhees71 said:
Hint
[tex]x \sin(1/x)=\frac{\sin(1/x)}{1/x}.[/tex]

Ahh thank you! Then you use l'hospital's Rule?
 
I wouldn't. This limit is related to this well-known limit
$$\lim_{t \to 0}\frac{sin(t)}{t}$$
 
Mark44 said:
I wouldn't. This limit is related to this well-known limit
$$\lim_{t \to 0}\frac{sin(t)}{t}$$

What do you mean?
 
Hint 2: Use a substitution, then figure out what the appropriate change in the limit would be.
 

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