Question

This geometric sequence? What is the explicit formula for 8, 4, 2, 1, ...

Answer 1

Answer:

D

Step-by-step explanation:

the first term is 8, the ratio is 1/2 ( 8*1/2 = 4, 4*1/2 = 2, 2*1/2 = 1)

the formula for an explicit geometric formula is :

$a_{n} = a_{1} * r^{(n-1)}$

plug in your numbers :

$a_{n} = 8 * (\frac{1}{2}) ^{(n-1)}$