Is the Shaded Region Outside the Circle in the W Plane?

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Homework Help Overview

The discussion revolves around a problem involving the transformation of a region defined in the complex plane (Z-plane) to another region in the W-plane, specifically concerning the shading of areas inside or outside a circle based on a given condition.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the correct interpretation of the condition for complex numbers, questioning the notation used for defining regions in the Z-plane and how it relates to the transformation to the W-plane. There is an exploration of whether the shading should be inside or outside the circle based on the transformation.

Discussion Status

Some participants have provided clarifications regarding the notation and the implications of the transformation, suggesting that the original poster reconsider the relationship between the Z-plane and W-plane. Multiple interpretations of the shading based on the transformation are being explored, but no consensus has been reached.

Contextual Notes

There is a mention of a mark scheme indicating a different shading than what the original poster expected, leading to confusion about the transformation's effect on the region defined by the inequality.

trew
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Homework Statement


WeR5Bj4.png
[/B]

Homework Equations

The Attempt at a Solution



I had no problems with part a and was able to form the equation of the circle and get its centre/radius.

It's part b that I'm stuck on.

My notes show that for Z < 3 I would shade inside the circle but the mark scheme for this question is showing the circle but the region shaded is OUTSIDE the circle.

Does this have something to do with the transformation into the W plane?
 

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Hello Trew, :welcome:

You can't write ##{\bf z} < 3## for a complex number ... :rolleyes: it's ##|{\bf z}| < 3## as in the problem description.
The latter is inside the circle in the ##\bf z ## plane -- as in your notes

But the exercise asks for the image (the complex 'range') of the function (transformation), so, as you suspect, in the ##\bf w## plane.
 
BvU said:
Hello Trew, :welcome:

You can't write ##{\bf z} < 3## for a complex number ... :rolleyes: it's ##|{\bf z}| < 3## as in the problem description.
The latter is inside the circle in the ##\bf z ## plane -- as in your notes

But the exercise asks for the image (the complex 'range') of the function (transformation), so, as you suspect, in the ##\bf w## plane.

Hey BvU,

Appreciate the response and help.

So is it a case of it being the opposite if it is transformed into the W-plane?
 
You say already found the circle in the W plane ? Check where a pont with ##|{\bf z}| < 3## ends up !
And double check with some points with ##|{\bf z}| > 3## !
 

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