Question

The first 9 terms of a sequence are 8, 7, 5, 1, -7, -23, -55, -119, -247. Which recursive formula could have been used to produce these terms?

A) t1 = 8, tn = tn - 1 - 1, where n ∈N and n > 1
B) t1 = 8, tn = 2tn - 1 - 9, where n ∈N and n > 1
C) t1 = 8, tn = 3tn - 1 - 15, where n ∈N and n > 1
D) t1 = 8, tn = 4tn - 1 - 17, where n ∈N and n > 1

Answer 1

B.
`t_1=8, t_n = 2t_(n-1)-9`

Explanation:

Try them all and find that B works.