Using Cauchy's integral formula to evaluate integrals

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SUMMARY

The integral of the function (z/(z+9)^2)dz along the contour γ(t) = 2i + 4e^it, where 0 ≤ t ≤ 2π, evaluates to zero due to Cauchy's theorem. The function is holomorphic within the defined circle, as its singularity at -9 lies outside this contour. Therefore, the application of Cauchy's integral formula confirms that the integral yields a result of zero.

PREREQUISITES
  • Cauchy's integral formula
  • Complex analysis fundamentals
  • Understanding of holomorphic functions
  • Contour integration techniques
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  • Explore advanced applications of Cauchy's integral formula
  • Learn about singularities and their impact on contour integrals
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Students of complex analysis, mathematicians focusing on contour integration, and anyone seeking to deepen their understanding of Cauchy's integral formula and its applications.

Woolyabyss
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Homework Statement


Use Cauchy’s integral formula to evaluate the integral along γ(t) of (z/(z+9)^2)dz
where γ(t) = 2i + 4e^it , 0 ≤ t ≤ 2π.

Homework Equations


Cauchy's integral formula

The Attempt at a Solution


I was just wondering is the integral not just zero by Cauchy's theorem since (z/(z+9)^2) is holomorphic inside the circle defined by γ(t) ( the singularity at -9 is outside the circle ).
 
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Woolyabyss said:

Homework Statement


Use Cauchy’s integral formula to evaluate the integral along γ(t) of (z/(z+9)^2)dz
where γ(t) = 2i + 4e^it , 0 ≤ t ≤ 2π.

Homework Equations


Cauchy's integral formula

The Attempt at a Solution


I was just wondering is the integral not just zero by Cauchy's theorem since (z/(z+9)^2) is holomorphic inside the circle defined by γ(t) ( the singularity at -9 is outside the circle ).
Yes, that seems to be the case.
 
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