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Find lim (-1)^[x] x->2 [x] is the greatest integer function

  1. Jun 28, 2008 #1
    find
    lim (-1)^[x]
    x->2

    [x] is the greatest integer function
    -> means tends to

    thanks to any help.
     
  2. jcsd
  3. Jun 28, 2008 #2

    CompuChip

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    Re: limits

    Start by plotting it. Then see if you can already find the limit from the graph. Only the final step is to try and prove it rigorously.
     
  4. Jun 28, 2008 #3

    HallsofIvy

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    Re: limits

    Looks straight forward to me. For all x larger than 1 but less than 2, [x]= 1 so the limit, as x approaches 2 from below is (-1)1= -1.

    For x larger than 2 but less than 3, [x]= 2. So what is the limit as x approaches 2 from the above? And what does that tell you about the limit itself?
     
  5. Jul 5, 2008 #4
    Re: limits

    Looks to me that the limit does not exist.
    There are different answers for the +ve and -ve limit.
     
  6. Jul 5, 2008 #5

    CompuChip

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    Re: limits

    Are aniketp and lizzie the same person? Or did you decide to just give away the answer after a week without reply from the OP?
     
  7. Jul 5, 2008 #6

    HallsofIvy

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    Re: limits

    After a week, I would suspect that the OP just can't be bothered to look at the responses and see nothing wrong with posting the answer- in case someone else is interested.
     
  8. Jul 5, 2008 #7

    CompuChip

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    Re: limits

    I agree, I just found it odd that someone who apparently has nothing to do with the thread posted this a week after the last message. I suppose on my list it would have dropped to page 40 or something by then :smile:
     
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