Singularity and residue theorem

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SUMMARY

The discussion focuses on the identification of singularities and the calculation of residues for the function f(z) = e^{-2z}/(z+1)^2. The participant correctly identifies the singularity at z = -1 and computes the residue using the limit method. The residue is confirmed to be -2e^2, validated by Mathematica. This demonstrates the application of residue theorem techniques in complex analysis.

PREREQUISITES
  • Understanding of complex analysis concepts, specifically singularities and residues.
  • Familiarity with the residue theorem and its applications.
  • Proficiency in using mathematical software like Mathematica for verification.
  • Knowledge of limits and derivatives in the context of complex functions.
NEXT STEPS
  • Study the residue theorem in detail to understand its implications in complex integration.
  • Learn advanced techniques for finding residues, including higher-order poles.
  • Explore the use of Mathematica for complex analysis problems and verification of results.
  • Investigate other functions with singularities to practice residue calculations.
USEFUL FOR

Students and professionals in mathematics, particularly those specializing in complex analysis, as well as anyone interested in mastering the residue theorem and its applications in evaluating integrals.

MissP.25_5
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Hello.
Can someone check if I got the answer right?

Find the singularity and the residue.

##f(z)=\frac{e^{-2z}}{(z+1)^2}##

My solution:

##f(z)=\frac{e^{-2z}}{(z+1)^2}##
$$Resf(z)_{|z=-1|}=\lim_{{z}\to{-1}}\frac{d}{dz}((z+1)^2\frac{e^{-2z}}{(z+1)^2})$$

$$\lim_{{z}\to{-1}}-2e^{-2z}=-2e^{2}$$
 

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A check with Mathematica tells me that your solution is correct :-).
 
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