Question

An arithmetic sequence is represented by the explicit formula A(n) = 2 + 9(n - 1). What is the recursive formula?
A. A(n) = A(n - 1) + 2

B. A(n) = A(n - 1) + 9

C. A(n) = A(n - 1) - 9

D. A(n) = A(n - 1) - 2

Answer 1

help please

Answer 2

This may sound silly, but you will want to write out the first 5 or 6 terms in the sequence and then see what that pattern is, as you can often pick it up visually. Remember doing this kind of thing on standardized tests and they'd ask you what the next number in the sequence should be? Same process really.

if n = 0 , then...
if n = 1, then...
etc.

Make sense? Post your sequence, the first 5, 6, or more terms of it and if you still can't pick up the pattern for the recursion I'll lend a hand as much as I reasonably can :-)

Answer 3

Actually I'd recommend starting at 1, here's the first 3. You do 3 more and if you can't easily guess the answer I'll point it out for you. Deal?

A(1) = 2
A(2) = 11
A(3) = 20
A(4) = ?
A(5) = ?
A(6) = ?

The wording of the problem is confusing. Just use your initial sequence, then see what each "next" (hint: next means A_(n-1), FYI) is increasing/decreasing by.