Assumptions in Integrate

*To*: mathgroup at smc.vnet.net*Subject*: [mg20562] Assumptions in Integrate*From*: Julian Aguirre Estibalez <mtpagesj at lg.ehu.es>*Date*: Sat, 30 Oct 1999 00:14:09 -0400*Organization*: Universidad del Pais Vasco/Euskal Herriko Unibertsitatea*Sender*: owner-wri-mathgroup at wolfram.com

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