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Find the sum of 3 +32 + 33 + ... + 38
6561
6560
9840
3280
To find the sum of the geometric series \(3 + 3^2 + 3^3 + \ldots + 3^8\), use the formula for the sum of a geometric series:
$$ S_n = a \frac{r^n - 1}{r - 1} $$
- Here, \(a = 3\) and \(r = 3\).
- The last term is \(3^8\), so there are 8 terms from \(3^1\) to \(3^8\).
- Apply the formula: \( S_8 = 3 \frac{3^8 - 1}{3 - 1} \).
- Calculate \(3^8 = 6561\).
- Substitute in the numbers:
$$ S_8 = 3 \frac{6561 - 1}{2} = 3 \times 3280 = 9840 $$
Therefore, the sum is 9840.
- Option 1: 6561 - This is \(3^8\) alone, not the sum.
- Option 2: 6560 - Incorrect for sum of series.
- Option 3: 9840 - This is the correct sum of the series.
- Option 4: 3280 - A miscalculation involving only \( \frac{6560}{2} \).
By: Parvesh Mehta ProfileResourcesReport error
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