Question

Find an explicit rule for the nth term of a geometric sequence where the second and fifth terms are -36 and 2304, respectively.

Answer 1

do you have a general idea?

Answer 2

i tried using this http://openstudy.com/study#/updates/513cdcd0e4b029b0182b5689

and i did
-36 - ar
2304 = ar^4
2304 = ar * r^3
2304 = -36 * r^3
2304 = r^3????????

Answer 3

with r being the common ratio
but i didn't get an integer

Answer 4

your second to last step looks correct

2304 = -36 * r^3

what happened to the -36 in the next step?
did you mean to divide the 2304 by that amount?

Answer 5

r^3=2304/-36=?

Answer 6

-64

Answer 7

\[r^3=\left( ? \right)^3\]
r=?

Answer 8

cube root it = 4?

Answer 9

no

Answer 10

4^3=64

Answer 11

\[r^3=-64=\left( -4 \right)^3,r=-4\]

Answer 12

does that mean it would be an = 9 * (-4)^n - 1?

Answer 13

correct.

Answer 14

YAY thanks :)))

Answer 15

yw