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Re: Limit of an Integer Function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg18839] Re: [mg18767] Limit of an Integer Function
  • From: BobHanlon at aol.com
  • Date: Thu, 22 Jul 1999 22:57:42 -0400
  • Sender: owner-wri-mathgroup at wolfram.com

Phil,

For the example given, you do not need the limit, you need Mathematica to 
make use of the fact that n is an integer.  In version 4, Simplify with the 
conditional that n is an element of the integers:

Simplify[Sin[n Pi], Element[n, Integers]]

0

Bob Hanlon

In a message dated 7/20/99 8:12:40 AM, mend0070 at tc.umn.edu writes:

>I seem to have found a blind spot in my knowledge of how to get
>Mathematica to evaluate limits.
>
>I want to evaluate the limit of a function where the domain is a member
>of the Natural numbers, such as infinite series.  It seems that Limit
>assumes that the function is continuous.
>
>For example, if I asked
>
>Limit[Sin[ n Pi ],n-> Infinity], mathematica would return: 
>Interval[{-1,1}].  This is true if n is a member of the Reals, but not
>true if n is a positive integer (in which case the limit would be 0.]
>
>Is there another function I should use?  Or would it be nice to specify
>the domain of the function as a feature request?
>


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