Basic Complex Analysis: Cauchy Riemann

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SUMMARY

The discussion centers on proving that if a holomorphic function f in the unit disc D1 has a constant real part, then its imaginary part must also be constant. This conclusion is derived using the Cauchy-Riemann equations, which are fundamental in complex analysis. The participants confirm that the connectedness of the unit disc D1 and the application of the mean value theorem support this proof. The discussion emphasizes the simplicity of this result compared to other similar problems that may require different approaches.

PREREQUISITES
  • Cauchy-Riemann equations
  • Holomorphic functions
  • Unit disc D1 in complex analysis
  • Mean value theorem
NEXT STEPS
  • Study the implications of the Cauchy-Riemann equations in complex analysis
  • Explore properties of holomorphic functions in different domains
  • Investigate the mean value theorem in the context of complex functions
  • Review examples of constant real and imaginary parts in holomorphic functions
USEFUL FOR

Students of complex analysis, mathematicians focusing on holomorphic functions, and educators teaching the fundamentals of Cauchy-Riemann equations.

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Homework Statement


Let f be a holomorphic function in the unit disc D1 whose real part is constant.
Prove that the imaginary part is also constant.

Homework Equations


Cauchy Riemann equations


The Attempt at a Solution


Hi guys, I'm working through the basics again. I think here we just need to use Cauchy Riemann and the fact that the unit disc D1 is connected?
 
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C-R equation should suffice given the real part of an analytic function is constant.
 
Yes I thought so, thanks. I knew this was a basic fact even though there are similar sounding problems that often use other tools. Anyways I guess the details are just an application of the mean value theorem.
 

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