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Péter J.
02/18/12 05:52am

Hello!

My problem is the following: I would like to solve a set of 3 equations, particularly nc^2/(Sqrt[(1 - v^2/c^2)]) == mc^2/(Sqrt[(1 - b^2/c^2)]) + pc and nv/Sqrt[1 - v^2/c^2] ==
mb/Sqrt[1 - b^2/c^2]*cos[\[Alpha]] + p*sin[\[Alpha]] and mb/Sqrt[1 - b^2/c^2]*sin[\[Alpha]] == p*cos[\[Alpha]] for v, b and p (I need v in terms of alpha, m, n and c). So I used the following:

Solve[{nc^2/Sqrt[1-v^2/c^2]==mc^2/Sqrt[1-b^2/c^2]+pc,nv/Sqrt[1-v^2/c^2]==(mb cos(\[Alpha]))/Sqrt[1-b^2/c^2]+p sin(\[Alpha]),(mb sin(\[Alpha]))/Sqrt[1-b^2/c^2]==p cos(\[Alpha])},{v,b,p}]

Unfortunately the output starts like:

{{v -> -(I c \[Sqrt](mc^4 nv^2 Cos[\[Alpha]]^2 -
2 mb mc^2 nc^2 nv Cos[\[Alpha]]^3 +
mb^2 nc^4 Cos[\[Alpha]]^4 - mb^2 pc^2 Cos[\[Alpha]]^4 -
2 mb mc^2 nc^2 nv Cos[\[Alpha]] Sin[\[Alpha]]^2 +
2 mb^2 nc^4 Cos[\[Alpha]]^2 Sin[\[Alpha]]^2 -
2 mb^2 pc^2 Cos[\[Alpha]]^2 Sin[\[Alpha]]^2 +
mb^2 nc^4 Sin[\[Alpha]]^4 -
mb^2 pc^2 Sin[\[Alpha]]^4))/(mb pc Sqrt[
Cos[\[Alpha]]^4 + 2 Cos[\[Alpha]]^2 Sin[\[Alpha]]^2 +
Sin[\[Alpha]]^4]), ... ... ...
And so on.

It is clear, that Mathematica 8.0.1 gave a solution for v, but v itself, p and b are involved as well, even though they are unknown as well! Why is this? Did I mistype sometthing, or forget something?

Any help is highly appriciated. I attached the notebook with the input and the output.

Thanks in advance!

Attachment: Output.nb, URL: ,

Subject (listing for 'Equation system solving problems')
Author Date Posted
Equation system solving problems Péter J. 02/18/12 05:52am
Re: Equation system solving problems Bill Simpson 02/29/12 00:19am
Re: Re: Equation system solving problems Juhász P. 03/10/12 09:50am
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