Re: Mathmatica Problem...
- To: mathgroup at smc.vnet.net
- Subject: [mg14355] Re: [mg14320] Mathmatica Problem...
- From: David Withoff <withoff>
- Date: Thu, 15 Oct 1998 00:28:57 -0400
- Sender: owner-wri-mathgroup at wolfram.com
> Dear mathgroup, > > We have just upgraded to release 3 of mathematica and we have found a > problem with the Expand function as described in the mathematica > manual. Here is the mathematica 3.0 output... > > In:= Expand[Cos[x]^3 Sin[x]^2,Trig->True] > > gives > > 3 2 > Out= Cos[x] Sin[x] > > this is not the answer given in the manual, which is... > > Cos[x] - Cos[3 x] - Cos[5 x] > ------ -------- -------- > 8 16 16 I am guessing that you are referring to the manual for Version 2. I didn't see this example in the Version 3 manual, but you can get this behavior in Version 3 using TrigReduce: In:= TrigReduce[Cos[x]^3 Sin[x]^2] //Expand Cos[x] Cos[3 x] Cos[5 x] Out= ------ - -------- - -------- 8 16 16 > We were led to believe that the new version was compatible with the > previous version. > > Is there a switch to obtain compatibility??? There is a listing "Incompatible Changes in Version 3.0" in Appendix A.13 of the Mathematica book, which mentions this change in the Trig option. It is always possible to get Version 2 behavior in Version 3, and most functionality that existed in Version 2 is identical or closely equivalent in Version 3, but there is not a switch that will cause Version 3 to be identical to Version 2 in every respect. > Any comments on this would be appreciated. Also who should I send this > to at Wolfram? You can send technical questions, comments, suggestions, etc., to Wolfram Research technical support at the address support at wolfram.com. Dave Withoff Wolfram Research