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Homework Help: Cauchy - Riemann Function in terms of Z

  1. Sep 7, 2014 #1
    1. The problem statement, all variables and given/known data

    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.

    2. Relevant equations

    3. The attempt at a solution

    Attached Files:

    • CR.jpg
      File size:
      41.6 KB
  2. jcsd
  3. Sep 7, 2014 #2
    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.

    Attached Files:

  4. Sep 7, 2014 #3


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    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.
  5. Sep 8, 2014 #4
    Thanks Dick, yes it was a sign problem.
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