Question

Find an explicit rule for the nth term of a geometric sequence where the second and fifth terms are 40 and 5000, respectively.

Answer 1

2nd term = a^r 5th term = ar^4 where a = first term and r = common ratio
you can find r by dividing 5th term by the 2nd and equating it to 5000/40

Answer 2

then find a by dividing 40 by r

nth term = ar^(n-1)

Answer 3

ar^4 / ar = r^3 = 5000/40
can u continue?

Answer 4

im trying to.

Answer 5

an = 8 • 5n - 2

an = 8 • 5n + 3

an = 8 • 5n - 1

an = 8 • 5n + 1

Answer 6

my answer choices

Answer 7

can you work ou what r is?

Answer 8

i have no clue what to do

Answer 9

r^3 = 5000/40 = 125
r is cube root of 125 - use ur calculator for this

Answer 10

5 cubed is 125