Question
A sequence is defined by the recursive formula f (n + 1) = f(n) – 2. if f(1) = 18, what is f(5)?
Answer
Using the recursive formula f(n + 1) = f(n) - 2, we can find f(2), f(3), f(4), and f(5) sequentially.
f(2) = f(1) - 2 = 18 - 2 = 16
f(3) = f(2) - 2 = 16 - 2 = 14
f(4) = f(3) - 2 = 14 - 2 = 12
f(5) = f(4) - 2 = 12 - 2 = 10
Therefore, f(5) is 10.