Solving Cauchy Residual Theorem for Holomorphic Function at z=2i

  • Context: Graduate 
  • Thread starter Thread starter Alekon
  • Start date Start date
  • Tags Tags
    Cauchy Theorem
Click For Summary

Discussion Overview

The discussion revolves around solving a problem related to the Cauchy Residual Theorem for a holomorphic function at the point z=2i. Participants explore the application of the theorem, the transformation of the function, and the calculation of residues.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant expresses confusion regarding the transformation of the numerator to the form e^i(z+3) and the factoring of the denominator into (z-2i)(z+2i), noting that only (z+2i) should be used since the function is holomorphic at z=2i.
  • Another participant proposes a numerical answer of 0.00477463 without detailing the reasoning behind it.
  • A different participant suggests that the answer is $$\frac{\sin (3)}{4 e^2}$$ and offers to explain their calculation process.
  • A later reply claims to have calculated the answer as -0.2, referencing a picture for further details.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the correct answer, as multiple competing numerical values are proposed without agreement on the methodology or correctness of each approach.

Contextual Notes

There are indications of missing steps in the calculations and potential misunderstandings of the application of the theorem, but these remain unresolved within the discussion.

Who May Find This Useful

Individuals interested in complex analysis, particularly those studying the Cauchy Residual Theorem and its applications in holomorphic functions.

Alekon
Messages
2
Reaction score
0
Alright so I posted a picture asking the exact question.

Here is my best attempt...

According to my professor's terrible notes, the numerator can magically turn into the form:

e^i(z+3)

when converted to complex. The denominator will be factored into

(z-2i)(z+2i)

but the function is only holomorphic at z=2i so only (z+2i) can be used.

From there the Res(f,2i)=g(2i) which is equal to what I believe is something like

e^(i(2i+3)/(4i)

It follows that

J=e^(-2+3i)*Pi

and sovling for the real part gives me an incorrect answer.

I might be missing some steps but I'm going off a theorem and it's really hard to relate to this problem. Help me PLEASE!
 

Attachments

  • Capture.PNG
    Capture.PNG
    6 KB · Views: 475
Physics news on Phys.org
Is it 0.00477463?
 
This is $$\frac{\sin (3)}{4 e^2}$$

Let me know if this is the answer. I can explain how i got it.
 
I finally calculated the answer... it turned out to be -0.2

See the picture if you're interested
 

Attachments

  • Capture.PNG
    Capture.PNG
    14.6 KB · Views: 487

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 6 ·
Replies
6
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K