Which infinite series converges?
∑n=1∞(1.1)n−1\sum_{n=1}^{\infty} (1.1)^{n-1}∑n=1∞(1.1)n−1
∑n=1∞(0.9)n−1\sum_{n=1}^{\infty} (0.9)^{n-1}∑n=1∞(0.9)n−1
∑n=1∞(−2)n−1\sum_{n=1}^{\infty} (-2)^{n-1}∑n=1∞(−2)n−1
∑n=1∞1n\sum_{n=1}^{\infty} 1^n∑n=1∞1n