I need to fit 10 data points (x,y) into this equation:
ay² + bxy + cx + dy + e = x²
It's told that this is a ellipse-like equation. I can't do it with usual curve fitting tools because it is not really a function (one x corresponds to 2 ys). I can't either use ellipse curve fitting because there is no c*x and d*y in an ellipse equation. Any ideas?
Thanks in advance.
EDIT: Both Oil and AK4749 gave right answer! Thank you guys!
It is a linear system with variables [a b c d e]. You can use \ to solve it:
x=rand(10,1);
y=rand(10,1);
[y.^2,x.*y,x,y,ones(numel(x),1)]\x.^2
ans =
-0.4437 %% a
1.1034 %% b
0.5337 %% c
-0.2808 %% d
0.0402 %% e
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