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Math Help - decreasing sequences

  1. #1
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    decreasing sequences

    how do you show that a=n/2^n is a decreasing sequence
    Last edited by CaptainBlack; August 5th 2009 at 10:48 AM. Reason: restore deleted question
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  2. #2
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    Quote Originally Posted by Lupus View Post
    how do you show that a=n/2^n is a decreasing sequence
    You need to show that a_{n} > a_{n+1}.

    Since  <br />
n > 1<br />

    then  <br />
2n > n + 1<br />

    then  <br />
n > \frac{n+1}{2}<br />

    then  <br />
\frac{n}{2^n} > \frac{1}{2^n} \frac{n+1}{2} = \frac{n+1}{2^{n+1}}<br />

    the desired result.
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  3. #3
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    thanks you have been a great help
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