Question

What is the explicit formula for the geometric sequence with this recursive formula? a1=-7

an=an-1*(1/3)
A. an=- 1/3*7^(n-1)
B. an=1/3*(-7)*^(n-1)
C. an=7*(- 1/3)^(n-1)
D. an=-7*(1/3)^(n-1)

Answer 1

D

Step-by-step explanation: A P E X

Answer 2

D.
`a_n= - 7( (1)/(3) )^(n - 1)`

Step-by-step explanation

The given explicit formula is

`a_1= - 7`

and

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

This implies that,

`r = (1)/(3)`

The explicit formula is given by:

`a_n=a_(1)( (1)/(3) )^(n - 1)`

We substitute the known values to get;

`a_n= - 7( (1)/(3) )^(n - 1)`