Re: Trigonometric simplification - newbe question

*To*: mathgroup at smc.vnet.net*Subject*: [mg49051] Re: Trigonometric simplification - newbe question*From*: Bill Rowe <readnewsciv at earthlink.net>*Date*: Tue, 29 Jun 2004 04:50:39 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

On 6/28/04 at 4:13 AM, fedderwi at uni-bremen.de (Christensen) wrote: >this is a Mathematica newbe question for sure: >Mathematica comes up with the following result: >(4*(2*a*Sin[(n*Pi)/2] - a*Sin[n*Pi]))/(n^2*Pi^2) >Now I have the additional assumption that n is element of {1,2,3, >...) (and a is real) >How do I tell Mathematica to take this into consideration and >remove the Sin[n*Pi] term? You can use Assumptions to specify your assumptions, i.e. Simplify[(4*(2*a*Sin[(n*Pi)/2] - a*Sin[n*Pi]))/(n^2*Pi^2), Assumptions -> {n \[Element] Integers}] which results in (8*a*Sin[(n*Pi)/2])/(n^2*Pi^2) But note the Sin[n*Pi] cannot be removed without additional assumptions since it evaluates to either -1, 0 or 1 for different intgers n. -- To reply via email subtract one hundred and four