How do i show that $\displaystyle \sum_{n=2}^{n}1/2^{n}\le0.5$ I know $\displaystyle \sum_{k=0}^{\infty}r^k=\frac{1}{1-r}$ but the above starts from n=2 so can't work it out. thanks for any help.
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Originally Posted by charikaar How do i show that $\displaystyle \sum_{n=2}^{n}1/2^{n}\le0.5$ I know $\displaystyle \sum_{k=0}^{\infty}r^k=\frac{1}{1-r}$ but the above starts from n=2 so can't work it out. thanks for any help. $\displaystyle \sum_{n=2}^{n}1/2^{n}=\sum_{j=0}^{n-2}1/2^{j+2}$
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