MathGroup Archive 2013

[Date Index] [Thread Index] [Author Index]

Search the Archive

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

  • To: mathgroup at smc.vnet.net
  • Subject: [mg131505] Re: question related to (-1)^(1/3)
  • From: Alan <alan.isaac at gmail.com>
  • Date: Wed, 14 Aug 2013 02:17:18 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • Delivered-to: l-mathgroup@wolfram.com
  • Delivered-to: mathgroup-outx@smc.vnet.net
  • Delivered-to: mathgroup-newsendx@smc.vnet.net
  • References: <gnqo3c$c95$1@smc.vnet.net> <go63gv$pnd$1@smc.vnet.net>

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

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 ...)

Thanks,
Alan Isaac



  • Prev by Date: Re: redefining builtin but keep original available
  • Next by Date: Re: How to import a mp4 file on Mathematica
  • Previous by thread: Re: redefining builtin but keep original available
  • Next by thread: Re: question related to (-1)^(1/3)