arithmetic sequences and series

Question

Find the indicated term of each arithmetic

sequence.

18. a10 for –1, 1, 3, ...

Answer 1

The formula for an arithmetic sequence is:

a1 = the first term

d = the common difference

In this problem

a1=-1

d=2 (The sequence is increasing by 2 for each term.

n=10 because you are trying to find the 10th term

Plug these in and solve

an=a1+(n-1)d

a10=-1+(10-1)(2)

a10=-1+18

a10=17