How can I generate the data for an eight '8' draw?

Hello, I would like to know how to generate the data for the shape of an eight. I've been trying with some hysteresis functions but nothing gets me close really.

Thank you very much

Answer 1

[David Sanchez]

You can try with this:

t=0:.1:2*pi;
x = -sin(t);
y = sin(t);
plot(t,x,'*',t,y,'+')

[David Sanchez]

To see the 8 shape:

plot(x,t,'*',y,t,'+')

[jadaslg]

Thank you very much! It's kind of what I wanted.

Is there any easy way to extract the x and y datapoints for this figure?

Answer 2

[Paulo Barbosa]

div = pi/50;       % Resolution
sz = 100;          % Number of Points in 2 Pi
th = zeros(1,sz);
th(1) = pi;        % Starting at (0,0) and going up.

for i = 2:sz
    th(i) = th(i-1)-div;
end
circ_x = fat*cos(th);
circ_y = fat*sin(th);
x1 = circ_x(1:26);
y1 = circ_y(1:26);

% -------------------------------------------
th(1) = 0;
for i = 2:sz*fat
    th(i) = th(i-1)+div*fat;
end
cos_x = th;
cos_y = fat*cos(th/fat);
x2 = cos_x(1:51);
y2 = cos_y(1:51);

% -------------------------------------------
th(1) = -pi/2;
for i = 2:sz
    th(i) = th(i-1)+div;
end
circ_x = fat*cos(th);
circ_y = fat*sin(th);
x3 = circ_x(1:51)+16;
y3 = circ_y(1:51);

% -------------------------------------------
x4 = x2';
x4 = flipud(x4);
x4 = x4';

y4 = y2';
y4 = flipud(y4);
y4 = -y4';

% -------------------------------------------
th(1) = -pi/2;
for i = 2:sz
    th(i) = th(i-1)-div;
end
circ_x = fat*cos(th);
circ_y = fat*sin(th);
x5 = circ_x(1:26);
y5 = circ_y(1:26);

% -------------------------------------------
x = [x1 x2 x3 x4 x5];
y = [y1 y2 y3 y4 y5];

% A plot so you can see each section
figure
hold on
plot(x1,y1,'.r');
plot(x2,y2,'.b');
plot(x3,y3,'.k');
plot(x4,y4,'.g');
plot(x5,y5,'.y');

[Hendrik Schäfer]

What is fat? Thanks in advance!

Answer 3

[Carmelo Fabrizio Blanco]

t = [0:0.001:10];

f = 10;

x = sin(2*pi*t*f);

y = sin(2*pi*t*2*f);

figure();

plot(x,y);