Question

4. What is the 8th term of the geometric sequence 3,.........,1,.....…........?

Answer 1

`6561`

1) Paying attention to that we can tell that the first term is 3 and the fourth term is 81

2) The immediate consequence is to tell that the common ratio is 3 and then we can write out the following sequence:

`\begin{gathered} 3,9,27,81,... \\ a_8=3^8=6561 \\ 3^4=81 \end{gathered}`

Therefore, the eighth term is 6561.