Question

When finding the 9th term in a geometric sequence with a common ratio of 2 and a first

term of 3;
which is the value of (n-1)?

Answer 1

8

Explanation:

Nth term of a geometric sequence is given as:

`t_n = a r^((n-1))` ...(1)

Plugging n = 9, a = 3 and r = 2 in the above equation, we find:

`t_9 = (3) (2)^(9-1)`

`t_9 = (3) (2)^(8)`... (2)

Comparing equations (1) & (2), we obtan:

(n - 1) = 8