how do you show that a=n/2^n is a decreasing sequence
Last edited by CaptainBlack; Aug 5th 2009 at 10:48 AM. Reason: restore deleted question
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Originally Posted by Lupus how do you show that a=n/2^n is a decreasing sequence You need to show that $\displaystyle a_{n} > a_{n+1}$. Since $\displaystyle n > 1 $ then $\displaystyle 2n > n + 1 $ then $\displaystyle n > \frac{n+1}{2} $ then $\displaystyle \frac{n}{2^n} > \frac{1}{2^n} \frac{n+1}{2} = \frac{n+1}{2^{n+1}} $ the desired result.
thanks you have been a great help
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