Re: Re: bug? f'[x]'

*To*: mathgroup at smc.vnet.net*Subject*: [mg90935] Re: [mg90914] Re: [mg90894] bug? f'[x]'*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Wed, 30 Jul 2008 03:53:11 -0400 (EDT)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <22482780.1217263035440.JavaMail.root@m08> <200807290539.BAA18274@smc.vnet.net>*Reply-to*: murray at math.umass.edu

Perhaps the actual trouble is that notations like f[x]' are in effect used all the time in traditional math notation. For example: (3x^2 + 5x - 8)' = 6x + 5, (sin x)' = cos x, (e^x)' = e^x Go look in just about any beginning calculus book. No wonder students don't understand calculus and functions when such clap-trap is taught. DrMajorBob wrote: > The right side of both equations is meaningless in Mathematica, so of > course they are not True. > > For a version of the second one, we do have > > D[f'[x], x] == f''[x] > > True > > Bobby > > On Mon, 28 Jul 2008 06:53:58 -0500, <Benjamin.R.Lewis at gmail.com> wrote: > >> G'day, >> >> In[]:= f'[x] =!= f[x]' && f''[x] === f'[x]' >> Out[]= True >> >> Can anyone explain this? >> >> -Ben >> >> > > > -- 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: bug? f'[x]'***From:*DrMajorBob <drmajorbob@att.net>