Which of the following is an infinite series? A) 3, 13, 23, 33, ...
OB) 3, -6, 12, -24, 48
C) 2 - 6 + 18 - 54+...
.
D) 4 + 8 + 16 + 32

Explanation:

The three dots or ellipses indicate the pattern goes on forever to infinity. So the answer is between choices A and C based on this alone. Choice A is a sequence while choice C is a series. A sequence is simply a list of values often in some kind of mathematical pattern. A series is where you add values from a sequence together. This distinction rules out choice A and makes choice C the answer.

Note: choice C is a geometric series with first term 2 and common ratio -3. The infinite series diverges because r = -3 is outside the range -1 < r < 1.