# Complex analysis help!Watch

#1
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#2
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1 week ago
#3
What have you done so far?
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#4
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#5
bump
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#6
anyone?????
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#7
at least gimme a hint
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1 week ago
#8
(Original post by Idg a damn)
at least gimme a hint
Note that . So by De Moivre's Theorem.

Therefore .

So if you can work out what is, then just take the real part of the answer to obtain .

To work out that sum, you can try and think about how is actually just a geometric series.
Last edited by RDKGames; 1 week ago
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#9
(Original post by Idg a damn)
Is here anything I can do to reduce the numerator into two different complex numbers?
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#10
(Original post by RDKGames)
Note that . So by De Moivre's Theorem.

Therefore .

So if you can work out what is, then just take the real part of the answer to obtain .

To work out that sum, you can try and think about how is actually just a geometric series.
I have already considered the sum to be a geometric series, I just need help in reducing the expression into what they want.
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#11
Is there anything I could use? A trig identity? Or something?
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1 week ago
#12
(Original post by Idg a damn)
Is there anything I could use? A trig identity? Or something?
I would really rather stick to summing up in terms of , and then at the end use the fact that
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#13
Managed to solve it just now, no thanks to you ( I wasn't being sarcastic nor was I trying to be offensive )
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