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Topic: Conic eccentricity through five points
Replies: 8   Last Post: Jul 22, 2013 2:08 PM

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 Wally W. Posts: 283 Registered: 6/15/11
Re: Conic eccentricity through five points
Posted: Jun 7, 2013 7:14 AM
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On Thu, 6 Jun 2013 06:20:30 -0700 (PDT), Narasimham wrote:

>Find eccentricity of a conic in terms of 5 points (x1,y1) to (x5,y5).( as there are 5 constants in a x^2 + 2 h x y + b y^2 + 2 f x + 2 g y = 1 )
>
>TIA
>Narasimham

Five equations with five unknowns. The constants can be found.

Then I would go here:

https://en.wikipedia.org/wiki/Rotation_of_axes

Starts with an equation similar to yours, with F = -1.

Last section:
Identifying rotated conic sections

Convert the equation to the standard form of the known shape, and plug
values into the equation for eccentricity.

It seems that it would be very tedious with many opportunities for
error, but doable.

Date Subject Author
6/6/13 Narasimham
6/6/13 Brian Q. Hutchings
6/7/13 Wally W.
6/7/13 Wally W.
6/12/13 Brian Q. Hutchings
6/12/13 Brian Q. Hutchings
6/21/13 Brian Q. Hutchings
6/23/13 Brian Q. Hutchings
7/22/13 Narasimham

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