Given the arithmetic sequence a_n = 2 - 5(n + 1), what is the domain for n? 
All real numbers
All integers where n ≥ 1
All integers where n > 1
All integers where n ≥ 2

Solution:

Option 2 is the answer.

A domain is ‘all the values’ that go into a function.

The domain of a function is the set of all possible inputs for the function.

Given:

Arithmetic sequence a_n = 2 - 5(n + 1)

⇒ a_n = 2 - 5n - 5

⇒ a_n = -5n - 3

The domain for n: 

All integers where n ≥ 1.

Given the arithmetic sequence a_n = 2 - 5(n + 1), what is the domain for n?

Summary:

For the given arithmetic sequence, a_n = -2 - 5(n + 1), the domain for n is, all integers where n ≥ 1.