Re: Different answers in mathematica and my calculator.

*To*: mathgroup at smc.vnet.net*Subject*: [mg125616] Re: Different answers in mathematica and my calculator.*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Thu, 22 Mar 2012 05:48:42 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201203211047.FAA27137@smc.vnet.net>*Reply-to*: murray at math.umass.edu

Informally, you're correct. But technically, you're not. After all, a real number _is_ complex. (One shouldn't confuse "non-real complex" with "complex.) On 3/21/12 6:47 AM, DrMajorBob wrote: > -1 is a real cube root of -1, so it's not quite correct to say "(-1)^(1/3) > is complex". > > Two cube roots of -1 ARE complex, of course. > > Bobby > > On Tue, 20 Mar 2012 02:21:56 -0500, psycho_dad<s.nesseris at gmail.com> > wrote: > >> I'm afraid that Sec corresponds to 1/Cos in the sense of 2 and 1/2 >> respectively. The function you want is ArcCos (inverse cosine). >> >> As for the first question, mathematica is right, so you are either doing >> something wrong on the calculator or it doesn't support complex numbers, >> as Power[2(-2)+3, (3)^-1]=(-1)^(1/3) is complex. >> > > -- 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**:**Re: Different answers in mathematica and my calculator.***From:*DrMajorBob <btreat1@austin.rr.com>