Fourier series

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 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

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?

He's asking why are the lines within the red circles there, I don't think he put them 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?

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.

I think you're right, for what it's worth: the lines which are circled in red should not be there.

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?

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??

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.

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.

I do not think there should be there ...

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?

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?

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.