Question

Identify the 13th term of the geometric sequence 10, 8, 6.4 …

Answer 1

The common ratio (r) for this is 8/10 = 6.4/8 = 0.8
First term is 10 (a)

And the formula to find the xth term is \[\huge x_n=ar^{n-1}\]

Answer 2

i dont know how to use the formula

Answer 3

\[\huge x_{15} = 10*0.8^{15-1} \approx 0.43\]

Answer 4

a13 ≈ 0.01

a13 ≈ 0.02

a13 ≈ 0.55

a13 ≈ 0.68
but it has to be one of these :3

Answer 5

Ohh, it's 13th, I'm sorry, I found the 15th :P

Answer 6

lol its okay :)

Answer 7

The one I gave you is the general formula to find pretty much any term in your sequence
The # is the 'n'th term you are looking for
so you plug 13 in (Not 15 haha).
\[\huge x_{13} = ar^{13-1}\]
Then a = 10, the first term
r = 0.8, common ratio
\[\huge x_{13} = 10 * 0.8^{13-1}\]
Solve:
\[\huge x_{13} = 10 * 0.8^{13-1} \approx 0.68\]

Answer 8

thank you