Question

What is the recursive rule for the sequence?

4.4, 5.8, 7.2, 8.6, 10, …



an=an+1+1.4 , where ​ a1=4.4 ​ ​ ​

an=an−1−1.4 , where ​ a1=4.4 ​ ​ ​

an=an−1+1.4 , where a1=4.4

an=an+1−1.4 , where ​ a1=4.4 ​ ​ ​

Answer 1

The next term is 1.4 larger than the one before it, so the appropriate choice is

`a_(n)=a_(n-1)+1.4 \quad\mbox{where}\ a_(1)=1.4`

_____

However, the description

`a_(n)=a_(n+1)-1.4 \quad\mbox{where}\ a_(1)=1.4`

also correctly describes the relationship between a1 and a2, for example. While this equation is technically correct, it is less useful to work with, so is probably not the expected answer.