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MathGroup Archive 2000

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Re: entering an equation

  • To: mathgroup at smc.vnet.net
  • Subject: [mg21603] Re: entering an equation
  • From: "Allan Hayes" <hay at haystack.demon.co.uk>
  • Date: Sun, 16 Jan 2000 22:43:49 -0500 (EST)
  • References: <85s1gr$ajj@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Mark

The message tells you what the difficulty is for Mathematica.
It arrises since

Log[2,x] is complex for  x<0,  Indeterminate for x=0 (though it may be
defined as -Infinity),  negative for 0<x<1, zero for x =1, positive for x>1


Check by evaluating

Table[{x, Log[2, Log[2, x]]}, {x, -1, 2, .2}] // ColumnForm





"Mark Woolard" <mark at ratbyte.com> wrote in message
news:85s1gr$ajj at smc.vnet.net...
> I am trying to plot a series of functions in Mathematica...one is giving
me
> trouble. I need : ln2 (ln2 x)
>
>     I enter: Log[2, Log[2,x]]
>
> and I get:
>
> is not a machine-size real \
> number at \!\(x\) = \!\(4.1666666666666667`*^-7\)."
>
> Does anyone have any suggestions?
>
>



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