Re: Help with non-linear system of equations (Trigonometric and Polynomial)

*To*: mathgroup at smc.vnet.net*Subject*: [mg115697] Re: Help with non-linear system of equations (Trigonometric and Polynomial)*From*: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>*Date*: Tue, 18 Jan 2011 05:53:12 -0500 (EST)*References*: <igrqbn$qna$1@smc.vnet.net>

You're looking at a conic section of an oblique cone with the line Pl- Pc as its axis, for A to be a constant. You might want to look up some texts on conic sections, quadrics, matrix representations of quadrics and coordinate transformations and so. You would also need to fit an ellipse to your six points. If you're using experimental data for the points, your original set of equations wouldn't have a solution, since that would require the points to lie on the ellipse with infinite precision. So fit first, then use the fit's parameters further on in the process. Cheers -- Sjoerd On Jan 15, 10:45 am, Manjinder Benning <manjbenn... at gmail.com> wrote: > Hi i am trying to do some 3D modeling by finding a 6 unknown 6 equation > simultaneous system. I am using the equation: > > Cos(a) = A.B/|A||B| > where A and B are lines (vectors) in 3 space. > a is the angle between the lines. > > When i run the calculation, Mathematica just runs forever and doesn't com= e > to a solution. It would be great if a closed form solution could be found=