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)

Respuesta :

ANSWER

D. [tex]a_n= - 7( \frac{1}{3} )^{n - 1}[/tex]

EXPLANATION

The given explicit formula is

[tex]a_1= - 7[/tex]

and

[tex]a_n=\frac{1}{3} a_{n-1}[/tex]

This implies that,

[tex]r = \frac{1}{3} [/tex]

The explicit formula is given by:

[tex]a_n=a_{1}( \frac{1}{3} )^{n - 1} [/tex]

We substitute the known values to get;

[tex]a_n= - 7( \frac{1}{3} )^{n - 1}[/tex]

Answer:

D

Step-by-step explanation: A P E X