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Any ellipse can be uniquely defined by five parameters i.e. center x0 and y0, semi-major aixs length a, semi minor axis length b, and orientation angle theta. I have parameters x0, y0, a, b, and theta. How can I exactly draw the ellipse?

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Some researches are necessary before to ask this kind of question. Mainly if the question was asked too much time.

You can do something like this :

Let (x1,y1) and (x2,y2) be the coordinates of the two vertices of the ellipse's major axis, and let e be its eccentricity.

 a = 1/2*sqrt((x2-x1)^2+(y2-y1)^2);
 b = a*sqrt(1-e^2);
 t = linspace(0,2*pi);
 X = a*cos(t);
 Y = b*sin(t);
 w = atan2(y2-y1,x2-x1);
 x = (x1+x2)/2 + X*cos(w) - Y*sin(w);
 y = (y1+y2)/2 + X*sin(w) + Y*cos(w):
 plot(x,y,'y-')
 axis equal

I don't have time to test it, but it should work. Next time, please read this section : How do I ask a good question

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Essex
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    Why answer if you yourself admit that this has been asked many times? – Suever Jun 21 '16 at 13:32
  • @Suever To help him even if I said that this question has been asked many times. Hopefully he will search more next time ^^ – Essex Jun 21 '16 at 13:34
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    @Andromedae93 however, that is not how Stackoverflow works! if you find a duplicate, mark it as duplicate, so we dont have a lot of the same thing around – Ander Biguri Jun 21 '16 at 13:36
  • @AnderBiguri Ok sorry ^^ – Essex Jun 21 '16 at 13:38
  • Set -1 is really ugly when someone gives the answer .. Yes it's a duplicate, but set negative point is not cool – Essex Jun 21 '16 at 13:53