Exercise Set 1.2, Question 7: Use the set-roster notation to indicate the elements in each of the following sets.
a. S = {n ∈ Z | n = (-1)^k, for some integer k}
b. T = {m ∈ Z | m = 1 + (-1)^i, for some integer i}
c. U = {r ∈ Z | 2 ≤ r ≤ -2}
d. V = {s ∈ Z | s > 2 or s < 3}
e. W = {t ∈ Z | 1 < t < -3}
f. X = {u ∈ Z | u ≤ 4 or u ≥ 1}