Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1999
*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 1999

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

Search the Archive

Re: Assumptions in Integrate

  • To: mathgroup at smc.vnet.net
  • Subject: [mg20579] Re: [mg20562] Assumptions in Integrate
  • From: Andrzej Kozlowski <andrzej at tuins.ac.jp>
  • Date: Sat, 30 Oct 1999 14:54:54 -0400
  • Sender: owner-wri-mathgroup at wolfram.com

I also think the Assumptions mechanism in Integrate leaves a lot to be
desired. Probably the best thing one can do right now is something like:

In[45]:=
Simplify[Integrate[Cos[n x], {x, -Pi, Pi},
           Assumptions -> Element[n, Integers]], Element[n, Integers]]

Out[45]=
0
-- 


> From: Julian Aguirre Estibalez <mtpagesj at lg.ehu.es>
> Organization: Universidad del Pais Vasco/Euskal Herriko Unibertsitatea
> Date: Sat, 30 Oct 1999 00:14:09 -0400
> To: mathgroup at smc.vnet.net
> Subject: [mg20579] [mg20562] Assumptions in Integrate
> 
> Dear Math Group,
> 
> I find the results of using assumptions in Integrate somewhat
> stranege. For instance,
> 
> In[21]:= Integrate[Cos[n x], {x, -Pi, Pi}]
> 
> Out[21]= 2 Sin[n Pi]
> -----------
> n
> 
> In[22]:= Integrate[Cos[n x], {x, -Pi, Pi},
> Assumptions -> Element[n, Integers]]
> 
> Out[22]=
> 2
> 2 Sin[Sqrt[n ] Pi]
> ------------------
> 2
> Sqrt[n ]
> 
> In[23]:= $Version
> 
> Out[23]= "4.0 for Power Macintosh (July 20, 1999)"
> 
> I know I can define my own transformation rules, but one would
> think that Mathematica should do it directly.
> 
> Julian Aguirre            | Voice:  +34 946012659
> Departamento de Matematicas    | Fax:    +34 944648500
> Universidad del Pais Vasco    | Postal: Aptdo. 644, 48080 Bilbao, Spain
> | email:  mtpagesj at lg.ehu.es
> 
> 



  • Prev by Date: Re: Zeta Function
  • Next by Date: Re: Re: Urgent Help needed
  • Previous by thread: Re: Assumptions in Integrate
  • Next by thread: Problems with EllipticE[p,1/k] - bug or property?