Complex Variable: Conformal Mappings

In summary, the conversation discusses transforming the region 0<Re(z)<pi/2 into the unit circle. The transformation process involves steps such as rotating pi/2, expanding the band onto the upper plane, and using a transformation formula. The individual asks if their approach is correct and if the transformation is conformal. They also mention needing to do a similar transformation with the intersection of two discs. After some discussion and confusion, they realize that the transformation can be simplified using the exponential function.
  • #1
ReyChiquito
120
1
Hello, i have this q.

The problem is that i need to transform the region 0<Re(z)<pi/2 into the unit circle. Now here is what I've done.

First i transform z_1=iz (rotate pi/2)
then z_2=Im(z_1)/(pi/2-Im(z_1)) (expand the band onto the whole upper plane)
and then z_3=(1/2+iz_2)/(1/2-iz_2) (transform the upper plain into the unit circle).

Now, substituting i get w(z)=(pi/2-Re(z)(1-2i))/(pi/2-Re(z)(1+2i)).

Is this correct?

Ive shown that the transformation is 1-1. Is this enough to state that is conformal or do i need to prove something else (that it is analytical, which is not clear for me). If so, what criteria would you suggest (less work)?

Plus, i need to do the same with the intersection of two discs (r=1 centers (1,0) and (0,1)) and in that case i have no clue how... should i send one part of the boundary to y=0 and the other to y=infinitum and then do the last transform or there is an easier way?

ps. sorry for bad english
 
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  • #2
pss... never mind... is much easier with the exponential function

i can't believe nobody tried to help me though... isn't a lot of mathematicians here?

did i post this in the wrong place?
 
  • #3


Hello there,

The steps you have taken to transform the region 0<Re(z)<pi/2 into the unit circle seem correct. You have successfully shown that the transformation is one-to-one, which is one of the criteria for a conformal mapping. However, to prove that it is conformal, you also need to show that it preserves angles. This can be done by considering a small angle in the original region and showing that it is equal to the angle in the transformed unit circle.

To prove that the mapping is analytical, you need to show that it is differentiable at every point in the region. This can be done by taking the derivative of the mapping function and showing that it exists and is continuous at every point in the region. This may require some additional work, but it is necessary to fully prove that the mapping is conformal.

As for the intersection of two discs, there are multiple ways to approach this problem. One possible approach is to use the same steps you used for the first problem, but with a different mapping function. Another approach would be to use a conformal mapping that is specific to this problem, such as the Schwarz-Christoffel mapping. This may require more work, but it will provide a more direct solution. It is up to you to decide which approach is more suitable for your problem.

I hope this helps! Good luck with your problem.
 

1. What is a complex variable?

A complex variable is a mathematical concept that involves numbers with both real and imaginary components. It is often represented in the form z = x + iy, where x is the real part and iy is the imaginary part.

2. What is a conformal mapping?

A conformal mapping is a function that preserves angles and the shape of small figures. In the context of complex variables, it is a function that preserves the complex structure of a region, meaning that it preserves the angles and shapes of curves in the complex plane.

3. How are complex variables and conformal mappings used in science?

Complex variables and conformal mappings are used in many fields of science, including physics, engineering, and mathematics. They are particularly useful in studying fluid dynamics, electromagnetism, and quantum mechanics.

4. What is the relationship between complex variables and real variables?

The relationship between complex variables and real variables is that complex variables extend the concept of real variables into the complex plane. Real variables deal with numbers on a single number line, while complex variables deal with numbers on a two-dimensional plane. Many properties of real variables also hold true for complex variables.

5. How do conformal mappings affect the shape of a region in the complex plane?

Conformal mappings do not change the overall shape of a region in the complex plane, but they can distort the shape of individual curves within the region. This distortion preserves the angles and shapes of curves, but can make them appear larger or smaller in certain areas of the region.

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