Select the correct answer. Select the function that defines the given sequence.
-8, -20, -50, –125, 625,...
ОА
- 1)
f(n) = -8-()
n-
OB.
- 1)
= -8.(29)
OC f(1) = -8
f(n) = f(n − 1), for n = 2, 3, 4, ...
OD. (1) = 8
f(n) = - . 1(n − 1), for n = 2, 3, 4, ...

Option C

Step-by-step explanation:

f(1) = -8

f(2) = -5/2×-8 = -20

f(3) = -5/2×-20 = -125

.

.

.

So option C is the answer

C.  a1 = -8

an = an-1 * 5/2  for n >1

Step-by-step explanation:

-8, -20, -50, –125, 625,...

We need to find the common ratio

Take the second  term and divide by the first term

-20/-8 = 5/2

Take the third term and divide by the second term

-50/-20 = 5/2

The common ratio is 5/2

A geometric sequence is

an = a1 * r^(n-1)

an = -8 *(5/2)^(n-1)

We can also write a recursive formula

a1 = -8

an = an-1 * 5/2  for n >1

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for