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

Question

Hero · Answer

Hint: Let n = 1. You should be able to find f(2). @e2 would you mind trying this?

Hero · Answer

Well, I'll help you compute f(2). Then you can try computing f(3). Deal? @e2

e2 · Answer

okay

Hero · Answer

Okay so to compute f(2), set n =1:
$\begin{align*}
f(1+1)&=f(1)-2\
f(2)&=f(1)-2\
f(2)&=18-2\
f(2)&=16
\end{align*}$

Hero · Answer

So the key to finding $f(2)$ is using the given information that $f(1) = 18$
We set $n = 1$, and use the recursive formula. Upon doing so $f(1)$ appears in the formula which we substiute $18$ in its place then continue computing $f(2)$. Do you understand what was done here?

e2 · Answer

i still dont get it

darkknight · Answer

thats tough