Answer:
(a) A sequence is an ordered list of numbers whereas a series is the sum of a list of numbers.
(b) A series is convergent if the sequence of partial sums is a convergent sequence, that is tends to a limit.
A series is divergent if it is not convergent.
Explanation:
(b) An example of a divergent series is the arithmetic series 2+ 4+6+8+10+...
The sum keeps increasing without bounds.
An example of a convergent series is 100 + 50, +25 + 12.5 +... a geometric series with common ratio 0.5 whose sum tends to a limit. The limit of this series is a1 / (1 - r) = 100 / (1 - 0.5) = 200.