Re: Re: transform a function
- To: mathgroup at smc.vnet.net
- Subject: [mg41528] Re: Re: transform a function
- From: David Terr <dterr at wolfram.com>
- Date: Sat, 24 May 2003 01:06:54 -0400 (EDT)
- References: <200305211204.IAA06950@smc.vnet.net> <3ECBC0E0.9030902@wolfram.com> <001401c32033$92cc7680$2d34c650@pc> <200305230726.DAA21630@smc.vnet.net> <3ECE236F.FDB0345F@wolfram.com>
- Sender: owner-wri-mathgroup at wolfram.com
Daniel Lichtblau wrote:
>David Terr wrote:
>
>>flemming wrote:
>>
>>>----- Original Message -----
>>>From: "David Terr" <dterr at wolfram.com>
To: mathgroup at smc.vnet.net
>>>
>>To: mathgroup at smc.vnet.net
>>
>>>To: "flemming" <flemmingjuul at hansen.tdcadsl.dk>
>>>Sent: Wednesday, May 21, 2003 8:09 PM
>>>Subject: [mg41528] Re:
>>>
>>>
>>>>flemming wrote:
>>>>
>>>>>Can you tell me how I can transform a function to a sum?
>>>>>Mathematica version 3,0 gives me f. eks:
>>>>>In=Sum[x^n/n!,{n,0,Infinity}]
>>>>>out=E^x
>>>>>But the opposite way.Which command?
>>>>>Thanks in advance.
>>>>>
>>>>Try Series.
>>>>
>>>>In[1]:= Series[E^x,{x,0,10}]
>>>>
>>>> 2 3 4 5 6 7 8 9 10
>>>> x x x x x x x x x
>>>>Out[1]= 1 + x + -- + -- + -- + --- + --- + ---- + ----- + ------ + ------- +
>>>> 2 6 24 120 720 5040 40320 362880 3628800
>>>>
>>>> 11
>>>>
>>>>> O[x]
>>>>>
>>>>David
>>>>What I should like to find is a command that
>>>>
>>>change a function to an infinit sum.
>>>f.eks:
>>>In=ArcTanh[x]
>>>(command)
>>>Out=[x^(2*n+1)/(2*n+1),{n,0,Infinity}]
>>>Thanks in advance.
>>>Flemming
>>>
>>>>
>>>>
>>To the best of my knowledge, no such function exists. I think this would
>>be difficult to write, by the way, since it would require trying to
>>identify a pattern in a given sequence of coefficients.
>>
>>David
>>
>
>RSolve`SeriesTerm will do this.
>
>http://forums.wolfram.com/mathgroup/archive/2003/May/msg00377.html
>
>Danny
>
My mistake, thanks!
David
- References:
- Re: transform a function
- From: David Terr <dterr@wolfram.com>
- Re: transform a function