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Re: A Bug in symbolic summation?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg113153] Re: A Bug in symbolic summation?
  • From: Christopher Arthur <aarthur at tx.rr.com>
  • Date: Fri, 15 Oct 2010 13:52:45 -0400 (EDT)
  • References: <201010140327.XAA06188@smc.vnet.net>

Hi Rex,

Hold[] and Simplify[] might help.

Chris.


Fancy Airex a écrit :
> I wish to do a basic symbolic manipulation of two summations.
>   
>>      Sum[f[i], {i, 0, m}] - Sum[f[i], {i, 0, j}]
>>     
>
> but can't get the expected result
>   
>>    Sum[f[i], {i, j+1, m}]
>>     
>
>
> I also tried
>   
>>    Sum[f[i], {i, 0, m}] - f[0]
>>     
>
> but can't get the expected result
>   
>>    Sum[f[i], {i, 1, m}]
>>     
>
>
> Though when I replace m with any definite number everything works
> fine.
>
> It seems that Mathematica can't change the minimum/maximum value of
> the summation variable i above in symbolic calculation...
>
>
> I also tried another system, but failed to do such symbolic computation.
>
> Did I miss any point here?
>
>
> Best,
> Rex
>
>
>   



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