Question

What are the explicit equation and domain for a geometric sequence with a first term of 4 and a second term of −8?

an = 4(−2)n − 1; all integers where n ≥ 0

an = 4(−2)n − 1; all integers where n ≥ 1

an = 4(−12)n − 1; all integers where n ≥ 1

an = 4(−12)n − 1; all integers where n ≥ 0

Answer 1

@kirbykirby

Answer 2

The first term a = 4

Find the common ratio 'r' first.
r = second term / first term

In the Geometric sequence: a, ar, ar^2, ....
the nth term is: a(r)^(n-1)

Answer 3

an = 4(−2)n − 1; all integers where n ≥ 0 ?

Answer 4

n >= 1

Answer 5

You can check which domain makes sense by plugging in values for the range of n given and she if it gives out the 1st and 2nd term

Answer 6

see*

Answer 7

"n" is the number of terms.
n = 1 refers to the first term
n = 2 refers to the second term
n = n refers to the nth term.

Answer 8

ok so an = 4(−2)n − 1; all integers where n ≥ 1?

Answer 9

yes.

Answer 10

thnks can you help with more?

Answer 11

I can try one more.