Question

Choose the correct explicit formula for the sequence below.

3, 6, 9, 12, 15


A. an=3 + 2(n - 1)
B. an=2 + 3(n - 1)
C. an=3 + 3(n - 1)
D. an=3 + 3(n)

Answer 1

an = 3+3(n-1)

Explanation:

We are adding 3 each time

6-3 = 3 9-6 = 3

The common difference is 3

The explicit formula for an arithmetic sequence is

an = a1+d(n-1)

The first term is a1 = 3

d =3

an = 3+3(n-1)