Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

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

Search the Archive

Re: Plotting a function -

  • To: mathgroup at smc.vnet.net
  • Subject: [mg71688] Re: Plotting a function -
  • From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
  • Date: Sun, 26 Nov 2006 03:49:27 -0500 (EST)
  • Organization: The Open University, Milton Keynes, UK
  • References: <ek990u$k88$1@smc.vnet.net>

Craig Reed wrote:
> Hi -
> 
> I'm trying to get Mathematica 5.2 to graph a function which is the ratio of 
> integers which have a '3' in them. Done in Exce3l, the graph of the first 
> 32,000 data points has a fractal look to it, especially when done with a 
> log scale.
> 
> What I've tried is the following
> 
> 
> f[x_] := Boole[DigitCount[x, 10, 3]]
> g[x_] := Sum[f, {i, x}]/x
> Plot[g, {x, 1, 100}]
> 
> 
> I get 3 errors of "g is not a michine-size real number at" followed by 3 
> real numbers:
> 1.000004125
> 5.016125.....
> 9.39607.....
> 
> What am I doing wrong?  or perhaps what I should ask is, "Is there a better 
> way?"
> 

The following version of your code should give you the expected graph:

f[x_] := Boole[DigitCount[x, 10, 3] > 0]
g[x_] := Sum[f[i], {i, x}]/x
Plot[Evaluate[g[x]], {x, 1, 100}];

Regards,
Jean-Marc


  • Prev by Date: Strange use of FrontEnd`FileName
  • Next by Date: RE: Partition
  • Previous by thread: Re: RE: Strange use of FrontEnd`FileName
  • Next by thread: Re: Plotting a function -