Re: Multiplication by 0: non-zero in versions 8 and 9

*To*: mathgroup at smc.vnet.net*Subject*: [mg131195] Re: Multiplication by 0: non-zero in versions 8 and 9*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Sun, 16 Jun 2013 05:20:55 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net*References*: <20130615082348.A15416A72@smc.vnet.net>

In fact, the Mathematica behavior you observe in later versions, while possibly disconcerting on strictly mathematical grounds, is reassuring on software consistency grounds. Thus, the 9.0.1 documentation page tutorial/ExactAndApproximateResults says: "Whenever you give a number with an explicit decimal point, Mathematica produces an approximate numerical result [for a calculation involving that number]." Personally, I would be unhappy if I did a calculation some of whose numbers were approximate yet whose answer gave a misleading exact answer. On Jun 15, 2013, at 4:23 AM, Sotirios Bonanos <sbonano at inp.demokritos.gr> wrote: > Hello , > > I have noticed that in all Mathematica versions <8, multiplying a real or complex number by the integer 0 gives 0, but in versions 8 and 9 > > Times[0, 0.567] gives 0. > > and > > Times[1.23 + I 2.45, 0] gives 0. + 0. I > > I don't know what prompted this change but it is definitely wrong: the zero property of multiplication holds for real and complex numbers also (see https://en.wikipedia.org/wiki/Multiplication#Properties) . > > Sotirios Bonanos > http://www.inp.demokritos.gr/~sbonano/ > --- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2838 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**Multiplication by 0: non-zero in versions 8 and 9***From:*Sotirios Bonanos <sbonano@inp.demokritos.gr>