how can plot the region of convergence?

hi all can you guide me how can plot the region of convergence? for example for below image?

thanks

Answer 1

[Image Analyst]

See the FAQ for how to create and plot circles http://matlab.wikia.com/wiki/FAQ#How_do_I_create_a_circle.3F

You can also use fill() or patch() to fill it with color, so you might plot a filled gray one, and then put "hold on" and place a smaller white one on top of it.

[sara]

thanks dear Image Analyst. I plot this in below.

I don't want to fill this circle. can you guide me how can I fill out of circle? thanks

this is my code:

    if true
      radius = 5; 
centerX = 0;
centerY = 0;
rectangle('Position',[centerX - radius, centerY - radius, radius*2, radius*2],...
    'Curvature',[1,1]);
axis square;
    end

[sara]

dear Image Analyst do you have any idea for intersection of this circle? thanks

[Image Analyst]

Try calling rectangle again with a smaller radius, so you'd have two of them.

[sara]

thanks. this work true :)

Is there any way to fill out of the circle? like below?

Answer 2

[Paul]

Since 2024a, radiusregion looks like a reasonable approach to get started.

For example, suppose the region of convergence is 0.5 < abs(z) < 1.5

h = polaraxes;
r = radiusregion(h,0.5,1.5);
h.RLim = [0 2];

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