Question

A sequence has a ratio of 4. When n = 1, the value of the function is 16. Which function models the sequence?

A: f(n)=4x4n

B:f(n)=4n+2

C:f(n)=fn+8

D:f(n)=2x4n

Answer 1

A.
`f(n)=4(4)^(n)`

Explanation:

The geometric sequence has the form:

`f(n)=ar^(n-1)`

where r=4 is the common ratio and
`a=16` is the first term.

When we plug in these values we obtain:

`f(n)=16(4)^(n-1)`

We can use properties of exponents to simplify further to get:

`f(n)=16((4)^(n))/(4^1)`

This gives us:

`f(n)=4(4)^(n)`

The correct answer is A.