Question

What is the tenth term of the geometric sequence with a4 = 16 and r = 2?

Answer 1

1024

Explanation:

for the standard 'Geometric sequence' , the terms are

a , ar , `ar^2 , ar^3 , ar^4 ,....................,ar^(n-1)`

where a , is the 1st term , r is the common ratio and the
nth term = `ar^(n-1)`
To find any term in the sequence , the nth term is used. To use it , requires knowing a and r .

To find a.

use `a_4 = ar^3 = 16 rArr a = 16/r^3 = 16/2^3 = 16/8 = 2`

now `a_10 = ar^9 = 2(2)^9 = 1024`