Re: Simple question or how Mathematica getting on my nerves.

*To*: mathgroup at smc.vnet.net*Subject*: [mg45788] Re: Simple question or how Mathematica getting on my nerves.*From*: bobhanlon at aol.com (Bob Hanlon)*Date*: Sun, 25 Jan 2004 03:04:43 -0500 (EST)*References*: <butdvt$9se$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

$Version 5.0 for Mac OS X (November 19, 2003) They aren't the same because you had the computations done at diifferent precisions. Different result indicates that there is a precision problem. Solution is to use higher precision. k[f_] := 2687176093959399272413585923303421161600* (1 - f)^67*f^61 N[Integrate[k[f], {f, 6214/10000, 5242/10000}]] -0.139838 N[Integrate[k[f], {f, 0.6214`45, 0.5242`45}]] -0.139838 Although NIntegrate works without explicitly increasing the precision. So the precision is impacted by the sequencing of the calculations. NIntegrate[k[f], {f, 0.6214, 0.5242}] -0.139838 Bob Hanlon In article <butdvt$9se$1 at smc.vnet.net>, gtsavdar at auth.gr (George) wrote: << Although the 2 results must be the same they aren't. WHY??????? And not only this, but they differ by 10^21!!!!!! WHY???????? Please copy and paste this to Mathematica (i tried 5.0 and 4.2) to understand what i mean: \!\(k[f_] := 2687176093959399272413585923303421161600\ *\((1 - f)\)\^67\ * f\^61\[IndentingNewLine] N[\[Integral]\_\(6214\/10000\)\%\(5242\/10000\)k[ f] \[DifferentialD]f]\[IndentingNewLine] N[\[Integral]\_0.6214\%0.5242 k[f] \[DifferentialD]f]\)