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Holomorphic 1/z
#15
2147483647 Wrote:
 Spoiler
Interestingly, WolframAlpha says that the integral is θ+i*log(1+3exp(iθWink). Then we run into the problem of taking the log the form that I was having trouble with earlier, namely the one I bolded and inferred:

log(3exp(4iπWink+1) - log(3exp(0i)+1) = 4πi


but e^(4 pi i) = e^(2 pi i) = e^(0 pi i) = 1, so log(3e^(4 i pi) + 1) = log(3 + 1) = log(3 e^(0 pi i) + 1), and that leaves us with zero?

2147483647 Wrote:This is precisely what I did, without shifting the "index" (aka I parametrized every line starting from (1,1) from 1 to -1 and then from -1 to 1 when I reached (-1,-1). I do see the problem now, however. In the last step, simplification had to be grouped:

∮1/z dz = ∫ 1/(t+i) dt [1,-1] + ∫ i/(-1+it) dt [1,-1] + ∫ 1/(t-i) dt [-1,1] + ∫ i/(1+it) dt [-1,1]
= ln(t+i) [1,-1] + ln(-1+it) [1,-1] + ln(t-i) [-1,1] + ln(1+it) [-1,1]
= {ln(1+i) - ln(-1+i)} + {ln(-1+i) - ln(-1-i)}+ {ln(-1-i) - ln(1-i)} + {ln(1-i) - ln(1+i)}
= ln[(1+1)/(-1+i)] + ln[(-1+i)/(-1-i)] + ln[(-1-i)/(1-i)] + ln[(1-i)/(1+i)]

And you claim that each one of these grouped logarithms is equivalent to πi/2.

No, I claim that specific result to be -2 pi i as you went clockwise instead of counterclockwise.

Also, Wolfram Alpha is partly correct, but look up complex logarithms! Some of them have infinitely many solutions.

Noah
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Messages In This Thread
Holomorphic 1/z - by 2147483647 - 2011-06-02, 07:44 PM
Holomorphic 1/z - by hadriel - 2011-06-02, 08:55 PM
Holomorphic 1/z - by 2147483647 - 2011-06-02, 11:07 PM
Holomorphic 1/z - by modular - 2011-06-03, 04:28 AM
Holomorphic 1/z - by 2147483647 - 2011-06-03, 04:32 AM
Holomorphic 1/z - by hadriel - 2011-06-03, 05:18 AM
Holomorphic 1/z - by 2147483647 - 2011-06-03, 05:25 AM
Holomorphic 1/z - by modular - 2011-06-03, 12:10 PM
Holomorphic 1/z - by hadriel - 2011-06-03, 04:42 PM
Holomorphic 1/z - by 2147483647 - 2011-06-03, 07:24 PM
Holomorphic 1/z - by hadriel - 2011-06-04, 04:58 AM
Holomorphic 1/z - by 2147483647 - 2011-06-04, 05:06 AM
Holomorphic 1/z - by Noah - 2011-06-04, 08:24 AM
Holomorphic 1/z - by 2147483647 - 2011-06-04, 08:34 AM
Holomorphic 1/z - by Noah - 2011-06-04, 08:45 AM
Holomorphic 1/z - by 2147483647 - 2011-06-04, 09:08 AM
Holomorphic 1/z - by Noah - 2011-06-04, 10:44 AM
Holomorphic 1/z - by modular - 2011-06-04, 05:28 PM
Holomorphic 1/z - by 2147483647 - 2011-06-04, 09:48 PM
Holomorphic 1/z - by hadriel - 2011-06-05, 03:42 AM
Holomorphic 1/z - by modular - 2011-06-05, 12:50 PM
Holomorphic 1/z - by 2147483647 - 2011-06-09, 09:50 AM
Holomorphic 1/z - by modular - 2011-06-09, 01:02 PM
Holomorphic 1/z - by 2147483647 - 2011-06-24, 10:34 AM
Holomorphic 1/z - by modular - 2011-06-27, 12:11 AM
Holomorphic 1/z - by 2147483647 - 2011-06-27, 12:35 AM

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