Re: Simplify[expr] bug?

*To*: mathgroup at smc.vnet.net*Subject*: [mg53408] Re: [mg53398] Simplify[expr] bug?*From*: Ken Tozier <kentozier at comcast.net>*Date*: Mon, 10 Jan 2005 01:42:02 -0500 (EST)*References*: <200501100404.XAA14039@smc.vnet.net> <41E21453.1080603@math.umass.edu>*Sender*: owner-wri-mathgroup at wolfram.com

On Jan 10, 2005, at 12:36 AM, Murray Eisenberg wrote: > NO, it's not a bug! > > Before attempting such things, it behooves you to read a couple of > pages of the documentation that accompanies Mathematica. Just about > ANY source of such documentation would explain that (in the default > input mode for Mathematica expressions), you surround arguments of > functions in [square brackets], whereas (parentheses) are used solely > as punctuation. > > What you entered means: Sin * a - Sin * b. so Mathematica correctly > simplfied that by factoring out the expression Sin. > > What presumably you want to enter is: > > Simplify[Sin[a] - Sin[b]] > > But since Mathematica knows nothing about a or b, it will return > Sin[a] - Sin[b] as result. > > The same problem is the case with your second alleged bug. > > Plesae try not to suggest attributing the term "bug" to Mathematica > behavior you do not yet understand! > > Best wishes for getting started productively with Mathematica. Duly chastised : ) I come from a C background so the "(" and ")" looked like a perfectly reasonable way to call a function. It's just one of those blind spot things. Thanks for the info. Ken > > > Ken Tozier wrote: >> I'm a complete newbie to Mathematica and not a math whiz, but the >> results I got from the following two equations seems like bugs to me. >> Test 1: >> Running: Simplify[Sin(a) - Sin(b)] >> Yeilds: (a - b)Sin >> Looks like it's treating the function "Sin" like a coefficient >> Test 2: >> Running: Simplify[d/s + Cos(2*¹*v/s) - Cos(2*¹*(v - 1)/s)] >> Yeilds: (d + 2 Cos ¹) / s >> Mathematica completely factors out the variable "v" which is critical >> to the correct solution. >> Are these bugs or am I making an inadvertent syntax error. >> Thanks, >> Ken Tozier > > -- > Murray Eisenberg murray at math.umass.edu > Mathematics & Statistics Dept. > Lederle Graduate Research Tower phone 413 549-1020 (H) > University of Massachusetts 413 545-2859 (W) > 710 North Pleasant Street fax 413 545-1801 > Amherst, MA 01003-9305 > >

**References**:**Simplify[expr] bug?***From:*Ken Tozier <kentozier@comcast.net>