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

MathGroup Archive 2008

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

Search the Archive

FindFit

  • To: mathgroup at smc.vnet.net
  • Subject: [mg92733] FindFit
  • From: Artur <grafix at csl.pl>
  • Date: Sat, 11 Oct 2008 06:47:47 -0400 (EDT)
  • References: <200810100835.EAA07169@smc.vnet.net>
  • Reply-to: grafix at csl.pl

Dear Mathematica Gurus,
Who have idea which procedure I can use inspite FindFit in following:
In[1]: Table[Simplify[Expand[(1/2) ((1 + Sqrt[13])^(2^n) + (1 - 
Sqrt[13])^(2^n))]], {n, 1, 6}]
Out[1]: {14, 248, 102272, 20489142272, 839425017825619607552,
1409268686920894404615927074915795024740352}
In[2]: FindFit[{14, 248, 102272, 20489142272, 839425017825619607552,
  1409268686920894404615927074915795024740352}, (1/
    2) ((a + Sqrt[b])^(2^x) + (a - Sqrt[b])^(2^x)), {a, b}, x,
 WorkingPrecision -> 100]
Out[2]:{a -> 2.43785286368448657933626328600,
 b -> 4.95343824602875750402007143975}

Should be: {a -> 1.00000000000000000000,
 b -> 13.000000000000000000}

Who have idea how find (true) a,b when I have sequence
Best wishes
Artur


  • Follow-Ups:
    • Re: FindFit
      • From: Andrzej Kozlowski <akoz@mimuw.edu.pl>
  • Prev by Date: Re: Prime Puzzle with Mathematica
  • Next by Date: Re: Mathematica vs Latex
  • Previous by thread: Unevaluated subtleties
  • Next by thread: Re: FindFit