Answer:
6 terms
Step-by-step explanation:
2 − 2/4 + 2/9 − 2/16 + ...
∑ (-1)ⁿ⁺¹ 2 / n²
Applying alternating series test:
lim(n→∞) 2/n² = 0
2/(n+1)² < 2/n², so the series is decreasing.
Therefore, the series converges.
2/(n+1)² < 0.05
(n+1)²/2 > 20
(n+1)² > 40
n+1 > 6.32
n > 5.32
n = 6
