Question

A sequence is defined by the recursive formula f (n + 1) = f(n) – 2. If f(1) = 18, what is f(5)?

Answer 1

`10`

Explanation:

The formula states that the next term in the sequence is generated by subtracting two from the previous one. We know that the first term is `18`, so we have

`f(1)=18`

`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`