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

Question

cwrw238 · Answer

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

cwrw238 · Answer

then find a by dividing 40 by  r

nth term = ar^(n-1)

cwrw238 · Answer

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

anonymous · Answer

im trying to.

anonymous · Answer

an = 8 • 5n - 2

 an = 8 • 5n + 3

 an = 8 • 5n - 1

 an = 8 • 5n + 1

anonymous · Answer

my answer choices

cwrw238 · Answer

can you work ou what r is?

anonymous · Answer

i have no clue what to do

cwrw238 · Answer

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

anonymous · Answer

5 cubed is 125