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Re: question related to (-1)^(1/3)

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  • Subject: [mg131505] Re: question related to (-1)^(1/3)
  • From: Alan <alan.isaac at>
  • Date: Wed, 14 Aug 2013 02:17:18 -0400 (EDT)
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  • References: <gnqo3c$c95$> <go63gv$pnd$>

Here is slightly different example of needing a domain restriction when using ``RecurrenceTable``:

    {xx[v + 1] - xx[v] == -3.0*Power[(xx[v + 1] + xx[v])/2.0, 3.0],
     xx[0] == 1.0},
     xx, {v, 0, 50}]

Q1: Is there a nice way in Mathematica 9 to restrict the domain to the reals?
Q2: If I use ``Re@Power`` instead of ``Power`` I get the expected output,
but I also get a bunch of warnings that "Function::slotn: Slot number 2 ... cannot be filled".  What is that about? (I'm not asking for the error documentation, but rather why this change produces that warning -- even if I should be able to get from the former to the latter ...)

Alan Isaac

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