How do you find the 8th term of -1, 1, 3, ...?

1 Answer
Mar 2, 2018

The 8th term in the sequence, a_8, is 13.

Explanation:

This appears to be an arithmetic sequence, as the numbers are increasing by 2 each time.

The formula for finding the nth term in an arithmetic sequence is:

a_n=a_1+(n-1)d

a_1, the first term in this sequence is -1.

d, or the common difference is 2.

Plug this information into the formula:

a_n=-1+(n-1)2

a_n=2n-3

Now plug in 8 for n to find a_8, or the 8th term in the sequence:

a_8=2(8)-3

a_8=13