Question

Which of the following correctly uses the explicit formula, An=1/4+(n−1)⋅1/2
, to find the 9th term of the described arithmetic sequence?(1 point)
Responses

Answer 1

Use n = 9:

A9 = 1/4 + (9 − 1)·1/2
= 1/4 + 8·1/2
= 1/4 + 4
= 17/4 = 4.25

So the correct choice is the one that gives A9 = 17/4 (or 4.25).