this geometric sequence?
What is the explicit formula for
8, 4, 2, 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 :
[tex]a_{n} = a_{1} * r^{(n-1)}[/tex]
plug in your numbers :
[tex]a_{n} = 8 * (\frac{1}{2}) ^{(n-1)}[/tex]