Using the ellipse graph.

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John Lutz
John Lutz il 30 Set 2017
Risposto: Ali Nafar il 13 Giu 2019
In polar coordinates (r,t), the equation of an ellipse with one of its foci at the origin is r(t) = a(1 - e2)/(1 - (e)cos(t)) I'm confused how to set this up, as I have never occurred an ellipse graph before. where a is the size of the semi-major axis (along the x-axis) and e is the eccentricity. Plot ellipses using this formula, ensuring that the curves are smooth by selecting an appropriate number of points in the angular (t) coordinate Thank you.
function untitled3
a = 1/2(b);
e = 0.5;
t = linspace(0,2*pi);
r = a(1 - e.^2)./(1 - (e)*cos(t));
plot(r,t)
axis equal
end

Risposte (3)

Image Analyst
Image Analyst il 30 Set 2017
You need to define b using a and e, not assume b is already defined like you did.
  1 Commento
John Lutz
John Lutz il 30 Set 2017
Still does not work, really confused on this.
t = linspace(0,2*pi);
e = 2*pi;
a = 1/2.*(2*pi);
r = (a.*(1 - e.^2) ./ (1 - ((e)*cos(t))));
axis equal
plot(r,t);
also this doesn't work either, tried many times to get this to work but it doesn't.

Accedi per commentare.


Henry Giddens
Henry Giddens il 30 Set 2017
Your equation ends up with some negative values - (which I'm not sure can be correct?), but if you are using polar coordinates, then use the polarplot or polar commands:
polarplot(t,abs(r))

Ali Nafar
Ali Nafar il 13 Giu 2019
L=0.5;
e=0.5;
phi0=0;
phi=linspace(0,2*pi);
rho=L*(1-e^2)./(1-e*cos(phi-phi0));
polar(phi,rho)

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