Question

A geometric sequence has these terms: a1 = 8, a2 = 20, az = 50, and a4 = 125.
Which formula can be used to find an?
O A. An = 8 + 12 (n-1)
OB. An = 8+ (n - 1)
OC. an = 8. 121-1
OD. an = 8()-1
O E. On = 8(?)"

Answer 1

Answer:

$a_{n}$ = 8$(2.5)^{n-1}$

Step-by-step explanation:

The n th term of a geometric sequence is

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

where a is the first term and r the common ratio

Here a = 8 and r = $\frac{20}{8}$ = 2.5, thus

$a_{n}$ = 8$(2.5)^{n-1}$