Calculate complex integral as line integral

In summary, the conversation discusses the calculation of a complex integral as a line integral. The participants suggest using numerical integration and checking the results symbolically by letting z=e^{it}. The suggestion is to compute the expression, compare it numerically and symbolically, and then evaluate the integral in t.
  • #1
evol_w10lv
71
0

Homework Statement


We need to calculate this complex integral as line integral:
mvw98gi92v0r12s9uk9w.png



Homework Equations





The Attempt at a Solution


This is correct, I guess:
v8yzkdwcftef6j9gch6p.png


But not sure about this part:
o09jbdaoynkhyxn1jg0x.png


Are dx, dy, x, y chages correct or there is other method to use?
 
Physics news on Phys.org
  • #2
evol_w10lv said:

Homework Statement


We need to calculate this complex integral as line integral:
mvw98gi92v0r12s9uk9w.png



Homework Equations





The Attempt at a Solution


This is correct, I guess:
v8yzkdwcftef6j9gch6p.png


But not sure about this part:
o09jbdaoynkhyxn1jg0x.png


Are dx, dy, x, y chages correct or there is other method to use?

Not hard to numerically integrate it and check your results right?

Code:
NIntegrate[(z^2 + z*Conjugate[z])*I*Exp[I*t] /. z -> Exp[I*t], {t, Pi, 0}]

but I just let [itex]z=e^{it}[/itex] to check that. What's wrong with just doing that symbolically from the start.
So my suggestion is for you to compute the expression your derived, compute it numerically in Mathematica or other, and thirdly, by letting [itex]z=e^{it}[/itex] and computing it by evaluating the integral in t and then compare the three.
 
  • #3
Of course... thanks for idea. I cheked results and they were equal.
 

Related to Calculate complex integral as line integral

1. What is a complex integral?

A complex integral is an integral that involves complex-valued functions. It can be thought of as a generalization of the real-valued integrals that are commonly used in calculus. Complex integrals are used to calculate the area under a curve in the complex plane, and they are also used in many areas of physics and engineering.

2. What is a line integral?

A line integral is a type of integral that is used to calculate the total value of a function along a given curve or path. It involves breaking the curve into small segments and taking the sum of the function values at each segment. Line integrals are commonly used in vector calculus to calculate work, flow, and other physical quantities.

3. How do you calculate a complex integral as a line integral?

To calculate a complex integral as a line integral, you first need to parameterize the curve or path that the integral will be taken over. This involves expressing the curve in terms of a single parameter, such as t. Then, you can use the fundamental theorem of calculus to convert the complex integral into a line integral, which can then be solved using standard techniques from vector calculus.

4. What are some applications of calculating complex integrals as line integrals?

Complex integrals as line integrals have many applications in mathematics, physics, and engineering. Some common examples include calculating work done by a force field, calculating fluid flow in a pipe, and solving problems in electromagnetism and quantum mechanics.

5. Are there any special techniques for calculating complex integrals as line integrals?

Yes, there are several special techniques that can be used to calculate complex integrals as line integrals. These include using Cauchy's integral formula, the residue theorem, and contour integration. These techniques can be particularly useful when dealing with complex functions that have singularities or when the path of integration is not a standard shape, such as a circle or rectangle.

Similar threads

  • Calculus and Beyond Homework Help
Replies
10
Views
724
  • Calculus and Beyond Homework Help
Replies
3
Views
629
  • Calculus and Beyond Homework Help
Replies
1
Views
654
  • Calculus and Beyond Homework Help
Replies
3
Views
593
  • Calculus and Beyond Homework Help
Replies
4
Views
1K
  • Calculus and Beyond Homework Help
Replies
12
Views
3K
  • Calculus and Beyond Homework Help
Replies
9
Views
252
  • Calculus and Beyond Homework Help
Replies
6
Views
2K
  • Calculus and Beyond Homework Help
Replies
7
Views
965
  • Calculus and Beyond Homework Help
Replies
2
Views
292
Back
Top