Find the sum to infinity of the geometric series 8 + 4 + 2 + 1 + ...
Answer and explanation
Correct answer: C. 16
- Step 1: a = 8 and r = 1/2, so the sum to infinity is a / (1 - r) = 8 / (1/2) = 16. Answer: 16. Why not the others: 15 adds only the first four terms, 16/3 uses 1 + r instead of 1 - r, and the sum is not infinite because |r| < 1, so the series converges.
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