Question

What is an explicit formula for an arithmetic sequence with a common difference of -2 and whose first term is one?

Answer 1

`a_(n)` = - 2n +3

Explanation:

the explicit formula for an arithmetic sequence is

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

here a₁ = 1 and d = - 2 , then

`a_(n)` = 1 - 2(n - 1) = 1 - 2n + 2 = - 2n + 3