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# Fourier series watch

1. I don't understand how they got the lines circled in red? The period is 2pi so surely the lines circled in red should not be there?
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2. (Original post by GPODT)

I don't understand how they got the lines circled in red? The period is 2pi so surely the lines circled in red should not be there?
it is because the period is 2pi
3. (Original post by GPODT)

I don't understand how they got the lines circled in red? The period is 2pi so surely the lines circled in red should not be there?
I think you're right, for what it's worth: the lines which are circled in red should not be there.
4. (Original post by TeeEm)
it is because the period is 2pi

(Original post by GPODT)

I don't understand how they got the lines circled in red? The period is 2pi so surely the lines circled in red should not be there?
correction I did not really read properly
I read "I do not understand why the red lines should not be there"

The answer is they are NOT

which now I wonder, why did YOU put them there?
5. (Original post by TeeEm)
correction I did not really read properly
I read "I do not understand why the red lines should not be there"

The answer is they are NOT

which now I wonder, why did YOU put them there?
He's asking why are the lines within the red circles there, I don't think he put them there.
6. (Original post by Phichi)
He's asking why are the lines within the red circles there, I don't think he put them there.
I only ask because it is handwritten and the other day he was asking about a different question on partial differentiation and I remember his strikingly neat handwriting.
7. (Original post by TeeEm)
correction I did not really read properly
I read "I do not understand why the red lines should not be there"

The answer is they are NOT

which now I wonder, why did YOU put them there?
(Original post by TeeEm)
I only ask because it is handwritten and the other day he was asking about a different question on partial differentiation and I remember his strikingly neat handwriting.
(Original post by Smaug123)
I think you're right, for what it's worth: the lines which are circled in red should not be there.
(Original post by Phichi)
He's asking why are the lines within the red circles there, I don't think he put them there.
Just to clarify, my handwriting is nowhere near as neat lol. These are worked examples given to me by my lecturer. I drew red circles over the black lines that I think shouldn't be there? My question is: did my lecturer make a mistake in drawing these black lines (that I have circled in red) or am I missing something?
8. (Original post by GPODT)
Just to clarify, my handwriting is nowhere near as neat lol. These are worked examples given to me by my lecturer. I drew red circles over the black lines that I think shouldn't be there? My question is: did my lecturer make a mistake in drawing these black lines (that I have circled in red) or am I missing something?
I do not think there should be there ...
9. (Original post by GPODT)

I don't understand how they got the lines circled in red? The period is 2pi so surely the lines circled in red should not be there?
you're in sixth from and doing fourier series?? which exam board is this??
10. (Original post by Ilovemaths96)
you're in sixth from and doing fourier series?? which exam board is this??
clearly wrongly labelled
11. (Original post by Ilovemaths96)
you're in sixth from and doing fourier series?? which exam board is this??
Sorry this is actually undergraduate Engineering Mathematics lol. AFAIK, Fourier series isn't covered at A-Level.
12. (Original post by GPODT)
Sorry this is actually undergraduate Engineering Mathematics lol. AFAIK, Fourier series isn't covered at A-Level.
Lol i was thinking a lvel maths has become much harder suddenly haha. Yeah, I covered it recently too at uni
13. (Original post by Ilovemaths96)
Lol i was thinking a lvel maths has become much harder suddenly haha. Yeah, I covered it recently too at uni
To be honest, I don't think Fourier Series is much more difficult than some of the content in FP2 or FP3.
14. (Original post by GPODT)
To be honest, I don't think Fourier Series is much more difficult than some of the content in FP2 or FP3.
True, not difficult really. SHould have been included in the syllabus
15. (Original post by TeeEm)
I do not think there should be there ...
(Original post by Smaug123)
I think you're right, for what it's worth: the lines which are circled in red should not be there.

Why have they introduced n=2k-1 ? I got the answer without doing this so is there a specific reason they have introduced k?
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16. (Original post by GPODT)

Why have they introduced n=2k-1 ? I got the answer without doing this so is there a specific reason they have introduced k?
yes

(1 + (-1)n) alternates between 0 and 2
17. (Original post by TeeEm)
yes

(1 + (-1)n) alternates between 0 and 2
if i'm not mistaken, odd funtion have fourier series of cosines only and even functions have fourier series with sines only?
18. (Original post by Ilovemaths96)
if i'm not mistaken, odd funtion have fourier series of cosines only and even functions have fourier series with sines only?
the other way round

odd sine only
even cosine only
19. (Original post by TeeEm)
yes

(1 + (-1)n) alternates between 0 and 2
Ah, I see why they done so though it doesn't really speed up the working out process!

Thanks.
20. (Original post by GPODT)
Ah, I see why they done so though it doesn't really speed up the working out process!

Thanks.
it produces a neater expression at the end

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