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Re: Integrate vs. NIntegrate

• To: mathgroup at smc.vnet.net
• Subject: [mg51437] Re: [mg51419] Integrate vs. NIntegrate
• From: DrBob <drbob at bigfoot.com>
• Date: Sun, 17 Oct 2004 03:05:43 -0400 (EDT)
• References: <200410160821.EAA23758@smc.vnet.net>
• Reply-to: drbob at bigfoot.com
• Sender: owner-wri-mathgroup at wolfram.com

I get a different answer here (with version 5.0.1):

N[Simplify[Integrate[Log[f],{x,-Pi,Pi}]/(2*Pi)]]//InputForm

0.6931471805599453

NIntegrate[Log[f],{x,-Pi,Pi}]/(2*Pi)//InputForm

0.693147180559943 + 0.*I

Bobby

On Sat, 16 Oct 2004 04:21:20 -0400 (EDT), Carlos Felippa <carlos at colorado.edu> wrote:

> Which one is the correct answer?
>
> f=2+Cos[2 x]+ I*Sin[2 x];
>
> Print[ N[Simplify[ Integrate[Log[f],{x,-Pi,Pi}]/(2*Pi)]] //InputForm];
> 0.34657359027997264 + 1.5707963267948966*I
>
> Print[            NIntegrate[Log[f],{x,-Pi,Pi}]/(2*Pi)   //InputForm];
> 0.6931471805599428 + 0.*I
>
> I believe the second one, have doubts about the first.
>
>
>
>



-- 
DrBob at bigfoot.com
www.eclecticdreams.net

• References:
  • Integrate vs. NIntegrate
    • From: carlos@colorado.edu (Carlos Felippa)