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Groups > comp.soft-sys.math.mathematica > #3219

Re: How to find one expression in terms of another expression?

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Thanks for this answer.

On Jun 20, 7:37 pm, Ray Koopman <koop...@sfu.ca> wrote:
>
> Omit 'dt = t2 - t1'. Otherwise, every time you write 'dt'
> it will be replaced by 't2 - t1'. Here is all you need:
>
> In[1]:=
> T1 = (t1 - ((u x1)/c^2))/Sqrt[1 - (u^2/c^2)];
> T2 = (t2 - ((u x2)/c^2))/Sqrt[1 - (u^2/c^2)];
> dT = Simplify[T2 - T1] /. t2 - t1 -> dt
> {b,a} = CoefficientList[dT,dt]
>
> Out[3]= (c^2*dt + u*(x1 - x2))/(c^2*Sqrt[1 - u^2/c^2])
>
> Out[4]= {(u*(x1 - x2))/(c^2*Sqrt[1 - u^2/c^2]), 1/Sqrt[1 - u^2/c^2]}

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Thread

How to find one expression in terms of another expression? Jacare Omoplata <walkeystalkey@gmail.com> - 2011-06-19 23:29 +0000
  Re: How to find one expression in terms of another expression? Ray Koopman <koopman@sfu.ca> - 2011-06-20 23:37 +0000
    Re: How to find one expression in terms of another expression? Jacare Omoplata <walkeystalkey@gmail.com> - 2011-06-21 11:18 +0000
  Multiple use of Set on lists Jonathan Frazer <J.Frazer@sussex.ac.uk> - 2011-06-20 23:38 +0000
    Re: Multiple use of Set on lists Oleksandr Rasputinov <oleksandr_rasputinov@hmamail.com> - 2011-06-21 11:17 +0000
  Re: Multiple use of Set on lists Leonid Shifrin <lshifr@gmail.com> - 2011-06-25 09:31 +0000

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