Mathematics

Problem

For each of the following infinite series, state with justification whether it converges or diverges: a. (a)

4+2+1+\tfrac12+\cdots

b. (b)

5-3+1.8-1.08+\cdots

c. (c)

7+7.7+8.47+\cdots

d. (d)

-2+1-\tfrac12+\tfrac14-\cdots