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MathGroup Archive 1998

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Can it be done - easily?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg13211] Can it be done - easily?
  • From: "Barry Culhane" <barryc at schaffner.com>
  • Date: Mon, 13 Jul 1998 07:42:59 -0400
  • Organization: Schaffner Ltd.
  • Sender: owner-wri-mathgroup at wolfram.com

Myself and two workmates are software developers.  One guy wanted a
formula to calculate a result for the following equation...
     Z = sum of X/Y where X is a fixed number, and Y ranges from A-B in
fixed steps...
     i.e... X=10000 ; Y=100,200,300...1000
     i.e... Z= 10000/100 + 10000/200 + ... 10000/1000 =  292.896

He and I tried to figure out a simple formula to calculate it, but
couldn't. The third guy said it was *not* *possible* to derive a
formula - we think he's wrong, but can't prove it.  MathCad can solve
it in the blink of an eye, even if the value of Y ranges from 1 to 1e6
in steps of 1 !!!

Can anyone come up with a simple formula to give a reasonably accurate
result?  It is too slow to actually divide X by Y for each value of Y
as there may be 1000 or even 100,000 values of Y.

Thanks in advance...
> Barry Culhane
> Schaffner Ltd, Limerick, IRELAND



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