Question

Represent the geometric series using the explicit formula. 2, −8, 32, −128, … f(n) = 2 ⋅ (−4)(n−1) f(n) = 2 ⋅ (4)(n−1) f(n) = f(n − 1) ⋅ (−4) f(n) = f(n − 1) ⋅ (4)

Answer 1

Answer: $f(n)=2(-4)^{n-1}$

Step-by-step explanation:

The explicit formula for geometric series is given by :_

$f(n)=ar^{n-1}$

, where r= common ratio.

a= first term.

The given geometric series : 2, −8, 32, −128, …

First term = 2

Common ratio = $\dfrac{-8}{2}=-4$

Substitute the value of a and r in (1) , we get

$f(n)=2(-4)^{n-1}$

Hence, the representation of the given geometric series using the explicit formula : $f(n)=2(-4)^{n-1}$

Answer 2

Answer:

Option B

Step-by-step explanation:

I did the test and I got it right.