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+ | =A useful Geometric Series formula= | ||
<math>\sum_{n = M}^N \alpha^n = \frac{\alpha^M - \alpha^{N-1}}{(1 - \alpha)}</math> | <math>\sum_{n = M}^N \alpha^n = \frac{\alpha^M - \alpha^{N-1}}{(1 - \alpha)}</math> | ||
*What if <math>\alpha=1</math>???? | *What if <math>\alpha=1</math>???? | ||
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+ | *For what values of M and N does this formula hold? Can they both be negative? Does N need to be greater than M? | ||
+ | ---- | ||
+ | [[More_on_geometric_series|Back to page on Geometric Series]] |
Revision as of 07:41, 29 September 2010
A useful Geometric Series formula
$ \sum_{n = M}^N \alpha^n = \frac{\alpha^M - \alpha^{N-1}}{(1 - \alpha)} $
- What if $ \alpha=1 $????
- For what values of M and N does this formula hold? Can they both be negative? Does N need to be greater than M?