Thanks a lot. You're right.

Thanks a lot. You're right.

@Markiyan Hirnyk Thanks for your reply. Any other suggestion?! I really need it.

@Markiyan Hirnyk Thanks for your reply. Any other suggestion?! I really need it.

mapleprimes.mw SBC.txt @acer Thank you. I'm using Maple 14. I upload my worksheet. To run it you need a data file that I upload it, as well. I just want to join the red, green and blue points together. Maybe in some cases it does not seem to an ellipse. Then I think your notation works well only if I want an exactly ellipse form, but I don't want that really. 

mapleprimes.mw SBC.txt @acer Thank you. I'm using Maple 14. I upload my worksheet. To run it you need a data file that I upload it, as well. I just want to join the red, green and blue points together. Maybe in some cases it does not seem to an ellipse. Then I think your notation works well only if I want an exactly ellipse form, but I don't want that really. 

@Christopher2222 I tried with your notation. It seems simple and well. But the problem is that it does not plot a complete ellipse. I mean it does not connect the last points to the first one. Is there any way to join them toghether? Thanks.

@Christopher2222 I tried with your notation. It seems simple and well. But the problem is that it does not plot a complete ellipse. I mean it does not connect the last points to the first one. Is there any way to join them toghether? Thanks.

Thanks a lot for your complete and also complicated answer. Albeit I did not understand what you did exactly, but when I want to use your notation I getan error after "K:=Statistics...." like as:

Error, (in Statistics:-Fit) incorrect specification of initial values

What's the problem?

Also, can I plot the ellipse without the black points?

Thanks a lot for your complete and also complicated answer. Albeit I did not understand what you did exactly, but when I want to use your notation I getan error after "K:=Statistics...." like as:

Error, (in Statistics:-Fit) incorrect specification of initial values

What's the problem?

Also, can I plot the ellipse without the black points?

Thank you, but your notation does not work for my list and I'll have a very complicated plot like an oscillation. My list is as follows:

 B00 := [[.241, 0.2e-2], [.241, 0.3e-2], [.242, 0.], [.243, 0.5e-2], [.246, -0.3e-2], [.246, 0.6e-2], [.247, 0.6e-2], [.248, -0.4e-2], [.248, 0.6e-2], [.25, -0.5e-2], [.252, -0.6e-2], [.253, 0.6e-2], [.254, 0.6e-2], [.255, 0.6e-2], [.261, -0.9e-2], [.261, 0.5e-2], [.265, -0.1e-1], [.266, 0.4e-2], [.269, 0.3e-2], [.271, -0.11e-1], [.272, -0.11e-1], [.272, 0.2e-2], [.278, -0.11e-1], [.279, -0.11e-1], [.28, -0.11e-1], [.28, -0.2e-2], [.283, -0.1e-1], [.284, -0.9e-2], [.284, -0.6e-2]]

Do you have any other idea?

Thank you, but your notation does not work for my list and I'll have a very complicated plot like an oscillation. My list is as follows:

 B00 := [[.241, 0.2e-2], [.241, 0.3e-2], [.242, 0.], [.243, 0.5e-2], [.246, -0.3e-2], [.246, 0.6e-2], [.247, 0.6e-2], [.248, -0.4e-2], [.248, 0.6e-2], [.25, -0.5e-2], [.252, -0.6e-2], [.253, 0.6e-2], [.254, 0.6e-2], [.255, 0.6e-2], [.261, -0.9e-2], [.261, 0.5e-2], [.265, -0.1e-1], [.266, 0.4e-2], [.269, 0.3e-2], [.271, -0.11e-1], [.272, -0.11e-1], [.272, 0.2e-2], [.278, -0.11e-1], [.279, -0.11e-1], [.28, -0.11e-1], [.28, -0.2e-2], [.283, -0.1e-1], [.284, -0.9e-2], [.284, -0.6e-2]]

Do you have any other idea?

Thank you so much and good luck!

Thank you so much and good luck!

I found that if I remove "stiff=true" it takes less time. Thank you!