How can I write a function that draws a regular polygon with n sides in a polar coordinate plot?

Question

gm76 2013-3-7

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https://ww2.mathworks.cn/matlabcentral/answers/66299-how-can-i-write-a-function-that-draws-a-regular-polygon-with-n-sides-in-a-polar-coordinate-plot

评论： debashish panda 2022-8-29

I am unfamiliar with plotting with polar coordinates. Here is what I have so far, which does not work:

function polygon(sides) % Name number of sides of the polygon
degrees=360/sides; % Find the angle between corners in degrees 
radius=ones(1,sides) % Array of ones
theta=0:degrees:360 % Theta changes by the internal angle of the polygon
polar(theta, radius) % Plot
end

Thanks!

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Danielle Wojeski 2016-12-31

编辑：Walter Roberson 2016-12-31

在 MATLAB Online 中打开

%First you need to define the sides variable.

sides=input('input the number of sides you want;, ')

Then you need to make sure the radius and the theta match in size. If your theta starts at 0 it will always be one size bigger then your radius. So instead make it a 1.

It should look like this...

function polygon(sides) % Name number of sides of the polygon
sides = input('input the number of sides you want;, ');
degrees = 360./sides; % Find the angle between corners in degrees 
r = ones(1,sides) % Array of ones
theta = 1:degrees:360 % Theta changes by the internal angle of the polygon
polar(theta, r) % Plot
end

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Answer 1

Azzi Abdelmalek 2013-3-7

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/66299-how-can-i-write-a-function-that-draws-a-regular-polygon-with-n-sides-in-a-polar-coordinate-plot#answer_77802

在 MATLAB Online 中打开

close
sides=5
degrees=2*pi/sides 
theta=0:degrees:360-degrees 
radius=ones(1,numel(theta)) 
polar(theta,radius)

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gm76 2013-3-7

Thanks so much, this works! Why is it that degrees seems to be defined in radians, (2*pi/sides) but is then subtracted from 360?

Azzi Abdelmalek 2013-3-7

在 MATLAB Online 中打开

I can't for the moment explain this, It was an error, it should be

sides=9
degrees=2*pi/sides 
theta=0:degrees:2*pi
radius=ones(1,numel(theta)) 
polar(theta,radius)

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Answer 2

Carson Cooper 2017-2-13

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/66299-how-can-i-write-a-function-that-draws-a-regular-polygon-with-n-sides-in-a-polar-coordinate-plot#answer_254519

编辑：Carson Cooper 2017-2-13

This gives a better output than those above

function polygon(sides)

sides = input('input the number of sides you want;, ');

radians = (2*pi)./sides;

r = ones(1, sides);

theta = 1:radians:2*pi;

polar(theta, r)

end

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Anders Bray 2022-7-11

theta includes 0 as the first step making it an 1x(sides+1) that is why have to accomidate.

debashish panda 2022-8-29

在 MATLAB Online 中打开

for n=3:1:6
    subplot(2,2,n-2)
    polygon(n)
end
function polygon(sides)
radians = (2*pi)./sides;
r = ones(1, sides+1);
theta = 0:radians:2*pi;
polar(theta, r)
end