       Re: Separating functions

• To: mathgroup at smc.vnet.net
• Subject: [mg128466] Re: Separating functions
• Date: Tue, 23 Oct 2012 00:54:17 -0400 (EDT)
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• References: <k603ld\$7lp\$1@smc.vnet.net>

```On Sunday, October 21, 2012 12:12:42 AM UTC-6, car... at colorado.edu wrote:
> Hi,
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> I have a problem in identification.  In the middle of the solution of a wave propagation problem on a regular lattice using a separation-of-variables method, I get a function of the form
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>                F(x,y,t)= f(x,y) g(t)
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> in which x,y are space coordinates and t is time. Both can be very complicated and vary from problem to problem, but Mathematica' Simplify is able to factor them. Here is a fairly trivial 1D example with an F output by //InputForm:
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>       Bx*(-5*Em - 3*Em*=CE=BD + 2*a^2*=CF=81*=CF=89^2 - 2*a^2*=CE=BD^2*=CF=81*=CF=89^2 + 4*Em*(1 + =CE=BD)*Cos[(a*kx)/
>
>           Sqrt] - Em*(-1 + =CE=BD)*Cos[Sqrt*a*kx])*(Cos[t*=CF=89] - I*Sin[t*=CF=89]))/(2*c0^2*(-1 + =CE=BD^2)*=CF=81)
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> Here g(t)=(Cos[t*=CF=89] - I*Sin[t*=CF=89])). For more complicated 2D cases, F(x,y,t) becomes a array of product functions, each taking 20-30 lines.
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> Question: is there a way to separate  f(x,y) and g(t) that does not require external intervention?
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> Thanks.

Actually this has nothing to do with the topic, but is about font mauling (see above)   Why does the new Google Groups
convert Mathematics  greek macros like \[Nu] to meaningless character combinations?  In the old Groups
they appeared like \[Nu] so the expression can be easily cut and pasted into a notebook.

```

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