Re: Factorising polynomials
- To: mathgroup at smc.vnet.net
- Subject: [mg63978] Re: [mg63970] Factorising polynomials
- From: Sseziwa Mukasa <mukasa at jeol.com>
- Date: Thu, 26 Jan 2006 03:43:00 -0500 (EST)
- References: <200601251346.IAA25881@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
On Jan 25, 2006, at 8:46 AM, Tony King wrote:
> I am trying to find the number of irreducible polynomials over the
> integers
> in the factorisation of x^n+1
>
> I used the following code
>
> data = Factor[x^# + 1] & /@ Range[6]
>
> Followed by
>
> Table[Length[data[[k]]], {k, 1, 6}]
>
> And Mathematica returned {2,2,2,2,2,2}, one assumes because it was
> counting
> terms such as 1+x as 2 terms. However, when the number of factors
> exceeds 1,
> Mathematica returns them as a list and counts them correctly. The
> output
> that I was looking for should have been {1,1,2,1,2,2}.
>
> Does anyone have any ideas how I might modify the above code so
> that it
> returns the correct number of terms
You could use something like
data = FactorList[x^# + 1] & /@ Range[6]
Table[Length[data[[k]]]-1, {k, 1, 6}]
Regards,
Ssezi
- References:
- Factorising polynomials
- From: "Tony King" <mathstutoring@ntlworld.com>
- Factorising polynomials