Cauchy - Riemann Function in terms of Z

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Homework Help Overview

The discussion revolves around finding the conjugate harmonic function for U(x,y)=sin(x)cosh(y) and expressing F(Z) in terms of Z. Participants are exploring the relationship between the variables and the simplification of the function using trigonometric identities.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to simplify the function in terms of Z and questions whether substituting x and y in terms of Z is sufficient. They express uncertainty about the simplification process and seek guidance on the direction to take.
  • Some participants discuss the use of trigonometric identities to rewrite hyperbolic functions and raise concerns about the analyticity of certain expressions.

Discussion Status

The discussion is active, with participants providing feedback on the original poster's approach. There is acknowledgment of a sign problem in the calculations, and one participant suggests showing steps in TeX for clarity. The conversation reflects a mix of exploration and clarification without reaching a consensus.

Contextual Notes

Participants are navigating the complexities of harmonic functions and their conjugates, with specific attention to the implications of analyticity and potential sign issues in their calculations.

KleZMeR
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Homework Statement



I found the function V, which is the conjugate harmonic function for U(x,y)=sin(x)cosh(y). I am attaching my work. It turns out to be a two-term function with trig factors. I am then to write F(Z) in terms of Z, but is plugging in x, and y, in terms of Z into my trig functions good enough? I think there's some simplification that can take place, i.e. Euler, as I started, but I am just wondering if there is a specific direction I should take to simplify before I crunch the math? There are many directions and this is my first problem like this. Any help would be appreciated.


Homework Equations





The Attempt at a Solution

 

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Ok, I think I simplified it in terms of Z, if anyone disagrees please let me know! I used cosh(y)=cos(i*y), and i*sinh(x)=sin(i*x) , and another often-used trig sub.
 

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KleZMeR said:
Ok, I think I simplified it in terms of Z, if anyone disagrees please let me know! I used cosh(y)=cos(i*y), and i*sinh(x)=sin(i*x) , and another often-used trig sub.

The harmonic conjugate of a function U is supposed the be the imaginary part of an analytic function where U is the real part. sin(z*) is NOT analytic. You have a sign problem and from your posted photos I can't tell where it came from. Try and show your steps in TeX. Or find it yourself.
 
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Thanks Dick, yes it was a sign problem.
 

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