Re: Series[log[x], {x, 0, 3}]
- To: mathgroup at smc.vnet.net
- Subject: [mg119124] Re: Series[log[x], {x, 0, 3}]
- From: Murray Eisenberg <murray at math.umass.edu>
- Date: Sun, 22 May 2011 06:56:36 -0400 (EDT)
Mathematica is doing exactly what you asked it to do -- because you typed a lower-case letter "l" for the log function. Presumably you want the built-in log function. Like all built-in functions, its name begins with an upper-case letter, "L". Thus you really want: Series[Log[x], {x, 0, 3}] And, because of the singularity at 0, the output you'll get is (in InputForm): SeriesData[x, 0, {Log[x]}, 0, 4, 1] Of course something like Series[Log[x], {x, 1, 3}] gives the expected result. On 5/21/2011 6:44 AM, Hongyi Zhao wrote: > Hi all, > > I do the following computation within Mathematica: > > Series[log[x], {x, 0, 3}] > > Then I get: > > log[0]+(log^\[Prime])[0] x+1/2 (log^\[Prime]\[Prime])[0] x^2+1/6 (log^(3)) > [0] x^3+O[x]^4 > > Any hints on this result? The log[0] is illegal in my mind. > > Regards. > -- > .: Hongyi Zhao [ hongyi.zhao AT gmail.com ] Free as in Freedom :. > -- 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