geometric sequence

Question

given the geometric sequence : 17, 170/3, 1700/9

Find an explicit formula for a_n

Find a₇.

Answer 1

The general formula for a geometric sequence is

an=a1(r)^n-1

an = the nth term

a1 = the 1st term

r = the common ratio

In this problem, a1=17

r=10/3

an=17(10/3)^n-1

To find the 7th term, n=7

a₇=17(10/3)^7-1

17000000/729