Integrating Complex Functions in the Complex Plane

In summary, the conversation discusses how to evaluate a line integral in the complex plane using direct integration. The equation used is Z= x+i y = Cos(θ) +i Sin(θ) = e^i*θ. The solution involves doing the integral with respect to z, and then substituting the limits for z, where the upper limit is z=x+iy=2pi + iy, y-->infinity. The conversation also acknowledges that the problem may have been overcomplicated at first due to the presence of the complex part in the upper bound.
  • #1
dykuma
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7

Homework Statement


Evaluate the following line integrals in the complex plane by direct integration.
upload_2016-11-13_21-56-9.png

Homework Equations


Z= x+i y = Cos(θ) +i Sin(θ) = e^i*θ

The Attempt at a Solution


I'm not sure how to evaluated this by hand. I tried using Z= x+i y = Cos(θ) +i Sin(θ), and evaluating the integral at dθ. However, I'm not sure how to change the bounds. It seems to me that point A starts at 2pi, and then point B is at 2pi + i *(infinity). what exactly does that mean?
 

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  • #2
dykuma said:

Homework Statement


Evaluate the following line integrals in the complex plane by direct integration.
View attachment 108889

Homework Equations


Z= x+i y = Cos(θ) +i Sin(θ) = e^i*θ

The Attempt at a Solution


I'm not sure how to evaluated this by hand. I tried using Z= x+i y = Cos(θ) +i Sin(θ), and evaluating the integral at dθ. However, I'm not sure how to change the bounds. It seems to me that point A starts at 2pi, and then point B is at 2pi + i *(infinity). what exactly does that mean?
You overcomplicate the problem. Do the integral with respect to z, as if it was a common real number. Then substitute the limits for z, using that the upper limit means z=x+iy=2pi + iy, y-->infinity.
 
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  • #3
ehild said:
You overcomplicate the problem. Do the integral with respect to z, as if it was a common real number.Then substitute the limits for z, using that the upper limit means z=x+iy=2pi + iy, y-->infinity.
I see. That is what I wanted to do at first. However, I was taken back by the complex part of the upper bound. I see now that I really over complicated that problem.

Thank you!
 

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1. What is the definition of a complex function?

A complex function is a mathematical function that takes a complex number as its input and produces a complex number as its output. It can be written in the form f(z) = u(x,y) + iv(x,y), where z = x + iy, u and v are real-valued functions of x and y, and i is the imaginary unit.

2. How do you integrate a complex function?

To integrate a complex function, you first need to express it in terms of its real and imaginary parts, u(x,y) and v(x,y). Then, you can use standard integration techniques for real-valued functions to integrate u(x,y) and v(x,y) separately. The resulting integrals can then be combined to get the final solution.

3. What are the common methods used for integrating complex functions?

The most common methods for integrating complex functions include the substitution method, partial fractions method, and contour integration. These methods are similar to the techniques used for integrating real-valued functions, but they are adapted for complex numbers and complex functions.

4. What are the benefits of integrating complex functions?

Integrating complex functions allows us to solve a wide range of problems in physics, engineering, and mathematics. It provides a powerful tool for understanding the behavior of complex systems and predicting their future states. Additionally, integrating complex functions can lead to new insights and discoveries in various fields of research.

5. What are some real-world applications of integrating complex functions?

Integrating complex functions is used in many practical applications, including signal processing, control theory, quantum mechanics, and electromagnetism. It is also commonly used in computer graphics and image processing to manipulate and analyze complex data. Furthermore, the study of complex functions has applications in economics, biology, and other social sciences.

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