A sequence of numbers is an ordered sequence of numbers whose domain is defined by the set of positive integers (or its finite subset ) . Each number in a sequence is called an item of the sequence. The number in the first place is called the first item of the sequence (usually called the first item), the number in the second place is called the second item in the sequence, and so on, the number in the nth place It is called the nth item of this sequence, usually represented by an.
Let's look at a topic
use example method
A. If xn diverges, 0,1,0,2,3..., yn is 0,0,0,0,0,0..., so A is wrong
B. If xn is unbounded 0,1,0,3,0,5..., yn is 0,2,0,4,0,6..., so B is wrong
C. If xn is bounded 0,0,0,0,0,0..., yn is 0,1,2,3,4,5,6..., so C is wrong.
Answer choice D