How do you show that a complex function is analytical?

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SUMMARY

The discussion focuses on demonstrating that complex functions such as sin z, cos z, and e^z are analytical using the Cauchy-Riemann relations. The participants confirm that for the function e^z, expressed as e^(x + iy) = e^x(cos(y) + i sin(y)), the real part u = e^x cos(y) and the imaginary part v = e^x sin(y) can be analyzed through the Cauchy-Riemann equations. This method effectively shows that these functions are indeed analytical in the complex plane.

PREREQUISITES
  • Understanding of complex functions and their representations
  • Familiarity with the Cauchy-Riemann equations
  • Knowledge of Euler's formula e^(iy) = cos(y) + i sin(y)
  • Basic concepts of real and imaginary parts of complex functions
NEXT STEPS
  • Study the Cauchy-Riemann equations in detail
  • Explore the properties of analytic functions in complex analysis
  • Learn about the implications of analyticity on function behavior
  • Investigate other complex functions and their analytical properties
USEFUL FOR

Mathematicians, students of complex analysis, and anyone interested in understanding the properties of complex functions and their analytical behavior.

twotaileddemon
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Like if I wanted to show how sin z, cos z, or e^z are analytical, what is the general process I have to do? Can I use the cauchy - riemann relations somehow?

(where z = x + iy is complex)
 
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Yes. For example, ez = ex+iy = exeiy =ex(cos(y) + i sin(y)) so

u = excos(y) and v = exsin(y)

and you can Cauchy-Riemann away.
 
Thanks! :)
 

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