Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2008

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

Search the Archive

Re: Exclude O[] from Series[] for Solve[] in Mathematica

  • To: mathgroup at smc.vnet.net
  • Subject: [mg92845] Re: Exclude O[] from Series[] for Solve[] in Mathematica
  • From: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>
  • Date: Wed, 15 Oct 2008 05:36:03 -0400 (EDT)

I expand a function as a Series[] but the O[] part prevents Solve[] from
working. I try Part[] and it returns something which also confuses
Solve[]. First[] works, but produces useless results, but this is why I am
sure this is what I want to do.

Hi, Vasos,
There is a function Normal[] that does the job. Compare:

In[5]:= Series[Sin[x], {x, 0, 5}]

Out[5]= (SeriesData[$CellContext`x, 0, {
 1, 0, Rational[-1, 6], 0, Rational[1, 120]}, 1, 6, 1])

with the following:

In[4]:= Normal[Series[Sin[x], {x, 0, 5}]]

Out[4]= x - x^3/6 + x^5/120

Check Help/Series for more details.

With this the Solve operator works:

In[7]:= Solve[Normal[Series[Sin[x], {x, 0, 5}]] == 0, x]

Out[7]= {{x -> 0}, {x -> -Sqrt[2 (5 - \[ImaginaryI] Sqrt[5])]}, {x -> 
   Sqrt[2 (5 - \[ImaginaryI] Sqrt[5])]}, {x -> -Sqrt[
    2 (5 + \[ImaginaryI] Sqrt[5])]}, {x -> Sqrt[
   2 (5 + \[ImaginaryI] Sqrt[5])]}}

Have success, Alexei

-- 
Alexei Boulbitch, Dr., Habil.
Senior Scientist

IEE S.A.
ZAE Weiergewan
11, rue Edmond Reuter
L-5326 Contern
Luxembourg

Phone: +352 2454 2566
Fax:   +352 2454 3566

Website: www.iee.lu

This e-mail may contain trade secrets or privileged, undisclosed or otherwise confidential information. If you are not the intended recipient and have received this e-mail in error, you are hereby notified that any review, copying or distribution of it is strictly prohibited. Please inform us immediately and destroy the original transmittal from your system. Thank you for your co-operation.




  • Prev by Date: Re: Variable amount of Buttons in Mathematica
  • Next by Date: Re: integration
  • Previous by thread: Re: Exclude O[] from Series[] for Solve[] in Mathematica
  • Next by thread: font substitutions