Which of the Following Are Alternating Series?
1) $\frac { ( - 1 ) ^ { 2 n } } { n }$

Multiple Choice

Which of the following are alternating series?
1) $\frac { ( - 1 ) ^ { 2 n } } { n }$
2) $\sum _ { n = 1 } ^ { \infty } \frac { ( - 1 ) ^ { n - 1 } } { n }$
3) $\sum _ { n = 1 } ^ { \infty } \frac { \cos n \pi } { n }$

A) None
B) 1
C) 2
D) 3
E) 1, 2
F) 1, 3
G) 2, 3
H) 1, 2, 3