Question

Formula for the geometric sequence 1/2, 1, 2, 4

Answer 1

an = 2n-2

Explanation:

correct answer got it right on test

Answer 2

`a_(n)` =
`(1)/(2)`
`(2)^(n-1)`

Explanation:

the nth term of a geometric sequence is

`a_(n)` = a₁
`(r)^(n-1)`

where a₁ is the first term and r the common ratio

here a₁ =
`(1)/(2)` and r =
`(a_(2) )/(a_(1) )` =
`(1)/((1)/(2) )` = 2 , then

`a_(n)` =
`(1)/(2)`
`(2)^(n-1)`