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Re: Bug? Analytical integration of cosines gets the sign wrong

• To: mathgroup at smc.vnet.net
• Subject: [mg107183] Re: [mg107168] Bug? Analytical integration of cosines gets the sign wrong
• From: Louis Talman <talmanl at gmail.com>
• Date: Fri, 5 Feb 2010 03:20:20 -0500 (EST)
• References: <201002041132.GAA00336@smc.vnet.net>

On Feb 4, 2010, at 4:32 AM, K wrote:

> the analytical integration in Mathematica 7.01.0 on Linux x86 (64bit)
>
> faultyInt =
> Integrate[Cos[ph]*1/Pi*Cos[4*ph]*Cos[2*ph], {ph, Pi, 3/2*Pi}]
>
> gives as result:
>
> 19/(105 \[Pi])

I get the same (incorrect) thing on an iMac running v7.01.0 under OS X  
10.5.8.  However if one computes first the indefinite integral and  
then substitutes the limits, one gets the negative---which is  
correct.  v6.0.1.0 and v5.0.1.0 both do the definite integration  
correctly.  Evidently v7 makes a bad choice of contour somewhere.


--Lou Talman
   Department of Mathematical and Computer Sciences
   Metropolitan State College of Denver

  <http://rowdy.mscd.edu/%7Etalmanl>

• References:
  • Bug? Analytical integration of cosines gets the sign wrong
    • From: K <kgspga@googlemail.com>