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Re: Expressions with ellipsis (...)

  • To: mathgroup at smc.vnet.net
  • Subject: [mg93028] Re: Expressions with ellipsis (...)
  • From: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>
  • Date: Fri, 24 Oct 2008 02:29:52 -0400 (EDT)

Hi, David,

the expression 

n^2 + (n - 1)^2 + (n - 2)^2 + ... + 1

is illegal itself. Instead you may use Sum[i^2, {i, n}] which is equivalent to your expression. Try the following:

In[60]:= Limit[Sum[i^2, {i, n}]/n^3, n -> Infinity]

Out[60]= 1/3

Alexei


Hi Mathematica Friends,

I want to do this:

Limit[(n^2 + (n - 1)^2 + (n - 2)^2 + ... + 1)/n^3, n -> Infinity]

But Mathematica barfs:

     expression cannot be followed by "...".

Searching the help for 'ellipsis' gives me the Unicode 2026 character
(i.e. ...).

How can I get Mathematica to eval this limit?

Thanks,
David.



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