2007 iTest Problems/Problem 5
From AoPSWiki
Problem
Compute the sum of all twenty-one terms of the geometric series
.
Solution
Those are powers of 2. So it would make sense to multiply the series by 2:
Subtracting,
See Also
| 2007 iTest (Problems) | ||
| Preceded by: Problem 4 | Followed by: Problem 6 | |
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