Show that f is entire when u is harmonic and v=

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SUMMARY

The discussion centers on proving that the function f, defined as f = u + iv where u is a harmonic function in R² and v is given by v(x,y) = ∫₀ʸ u_x'(x,t) dt - ∫₀ˣ u_y'(s,0) ds, is entire and analytic. The Cauchy-Riemann equations, specifically u_x' = v_y' and u_y' = -v_x', are crucial for establishing the analyticity of f. The harmonic nature of u implies that it satisfies Laplace's equation, which is essential for the proof. The notation u_x' is clarified as the derivative of u with respect to x, simplifying the analysis.

PREREQUISITES
  • Understanding of harmonic functions in R²
  • Familiarity with complex analysis concepts, particularly entire functions
  • Knowledge of the Cauchy-Riemann equations
  • Basic calculus, specifically integration and differentiation
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  • Study the properties of harmonic functions and their implications in complex analysis
  • Learn how to apply the Cauchy-Riemann equations in proving function analyticity
  • Explore examples of entire functions and their characteristics
  • Investigate the relationship between harmonic functions and potential theory
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Mathematicians, students of complex analysis, and anyone interested in the properties of harmonic and entire functions will benefit from this discussion.

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Homework Statement


Assume that u is harmonic everywhere in R^2, and let
[tex]v(x,y)=\int_0^y u_x'(x,t)dt - \int_0^x u_y'(s,0)ds[/tex]
show that f=u+iv is entire analytic.


Homework Equations


Maybe Cauchy Riemann: [tex]u_x'=v_y'[/tex] and [tex]u_y'=-v_x'[/tex]


The Attempt at a Solution


I have only tried to see what happens if I use the Cauchy Riemann equations, but I get stuck right away. I am not sure how to use the fact that u is harmonic either.

Any hints would be very appreciated.
 
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ux' is very strange notation. I think you mean just the derivative of u with respect to x- but that is just ux. There is no need for the ' here.

I have only tried to see what happens if I use the Cauchy Riemann equations, but I get stuck right away.
Good. Show what you did and where you got stuck.

I am not sure how to use the fact that u is harmonic either.
What does "harmonic" mean?
 

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