What is the half-range Fourier sine series for the function f(t) = t sin(t)?

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Homework Help Overview

The problem involves finding the half-range Fourier sine series for the function f(t) = t sin(t). The original poster expresses uncertainty regarding the limits for the series, as they are not specified in the question.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the potential limits for the series, with one suggesting standard limits of -π to π. Another participant proposes modifying the function to make it odd for the purpose of finding the Fourier series.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem. Some guidance has been offered regarding the transformation of the function, but there is no consensus on the correct approach or limits to use.

Contextual Notes

There is a noted lack of specified limits for the half-range Fourier sine series, which raises questions about the original problem statement. Additionally, participants are grappling with the implications of changing the function from t sin(t) to t cos(t) in the context of Fourier series.

NotStine
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Homework Statement



Question: Find the half-range Fourier sine series for the function f(t) = t sin(t)

Problem: According to all the examples I have gone through, they all have a limit when asking for the half-range. However, my teacher, in the question posted above, has not specified any limits. Is this a typing error? If not, can you please nudge me in the right direction.

Homework Equations





The Attempt at a Solution



None yet. I'm under the impression that question may have been typed wrong.
 
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I think -pi to pi are standard ...
Currently, it is an even function, I can suggest making it odd t*cos(t) and finding Fourier series from 0 to 2pi.
 
Ok here is what I gather so far:

I am looking for the sine half-series, which is bn.Sin(nt) from the Fourier series.

So,

bn = I{t.sin(t).sin(nt)} between 0 and 2pi

... which goes to ...

bn = I{t.sint(1+n)} between 0 and 2pi?

Is that correct?

EDIT: ... which gives me 0. I think I misunderstood.

Reading your suggestion again, you have changed t.sin(t) to t.cos(t)... Why is that? I can see we get an odd function (odd . even) but not sure how we came about the change...

Apologies in advance if I sound retarded, but 2 lectures on Fourier was no way near enough in my opinion.
 
Last edited:
Any ideas?
 

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