Question

Which recursive formula defines this sequence for n > 1?

3, 6, 9, 12, 15, 18, ...


Question 4 options:


an=3an−1


an=an−1+3


an=13an−1


an=an−1−3

Answer 1

(B)
`a_n=a_(n-1)+3`

Explanation:

Given the sequence: 3, 6, 9, 12, 15, 18, ...

6=3+3

9=6+3

12=9+3

If we continue in like manner, we notice that the nth term (
`a_n`) is an addition of 3 to the previous term (
`a_(n-1)`).

Therefore (for n>1), the recursive formula which defines the sequence is:

`a_n=a_(n-1)+3`

The correct option is B