Alternating Series Exploration

The nth partial sums are graphed for 3 sample series. Move slider n to see how adding terms to the sum impacts the partial sum. Do sample 1, 2, and 3 all converge? Diverge? Some converge, some diverge? How can you tell which one will converge? If you think the series converges, can you give a value to which it will converge? Is your value exact or an approximation?