Question

What is the recursive rule for an=4n−1?

Answer 1

the correct answer is the first one a1=3;an=an−1+4

Answer 2

Option 1 is correct that is
`a_1=3,a_n=a_(n-1)+4`

Explanation:

We have given
`a_n=4n-1`

We will put different values of n to get the recursive formula:

When n=1 in
`a_n=4n-1` we get

`a_1=4(1)-1=3`

When n=2 in
`a_n=4n-1` we get

`a_2=4(2)-1=7`

When n=3 in
`a_n=4n-1` we get

`a_3=4(3)-1=11`

We can clearly see the difference between consecutive terms is 4

Hence, recursive formula will become

`a_1=3,a_n=a_(n-1)+4`

Therefore Option 1 is correct that is
`a_1=3,a_n=a_(n-1)+4`