MathGroup Archive 1999

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: infuriating Series[] question

  • To: mathgroup at
  • Subject: [mg17257] Re: infuriating Series[] question
  • From: Jens-Peer Kuska <kuska at>
  • Date: Fri, 30 Apr 1999 02:34:43 -0400
  • Organization: Universitaet Leipzig
  • References: <7g0spa$>
  • Sender: owner-wri-mathgroup at

Hi Peter,

be a bit more clear what do you expect from Simplify[] and
That what you get from Series[] is *not* what you see !
You see a funny


that looks like a sum with a strange O[x]^3 term. But Mathematica has
saved it as


that means it is a series in x at x=0 with coefficients {a,b,c} with
exponet 0, maximal exponent 3 and the common denominator of the exponent

You can use Normal[] to convert the series to a polynom and some
like NumericalMath`Horner`Horner[] will now work. You may also
the coefficients of the series by

ser[[3]]=(Simplify /@ #) &[ser[[3]]]

but to give you a better advice I must know "what did you expect?"


Peter Jay Salzman wrote:
> Dear all,
> I'm trying to develop very high order difference equations, and want to use
> Mathematica to save me from calculating tons of quantities like 5^10 / 7!
> If I define:
>    g[x_] := Series[ f[x], {x,0,10} ]
> And try to compute stuff like:
>    g[5*h] or g[10*h]
> It gives me the right answer, but i get terms like
>    f'''''[0] * (5 x)^(10) / 10!
> The whole point in using Mathematica is so that I don't have to calculate things
> which look like 5^10 / 10!   (that's factorial, of course, not me being
> emphatic).
> Even when I try things like // Simplify or // FullSimplify, Mathematica refuses to
> simplify these rational coefficients.   One thing I've learned is that Mathematica
> can do anything -- but figuring out how to do the something is often
> completely not obvious to a nominal user like me.
> Can someone tell me the secret here?
> Pete

  • Prev by Date: Re: Question: getting list data into a matrix
  • Next by Date: Re: Complex Ratio Polynomial Fit
  • Previous by thread: Re: infuriating Series[] question
  • Next by thread: Re: infuriating Series[] question