Sequence
Definition: A function whose domain is the set of nonnegative integers
Examples:
2, 4, 6, 8
200, 100, 50, 25, …
Monday, Tuesday, Wednesday,…
Sequence Terms: Instead of representing sequences with function notation, we use subscripts.
Instead of 𝑓1=2, 𝑓2=4, and 𝑓𝑥=2𝑥,
We write
𝑎1=2
𝑎2=4
𝑎𝑛=2𝑛
(we often use the letter 𝑎, but sometimes we'll use a different letter for reasons that will be clear later)