Question

Given the following geometric sequence: 1,3,9,27,81,...

Write an explicit formula that describes this sequence.
Using the formula, find the 18th term of the sequence

Answer 1

The 18th term of the geometric sequence is
`a_(18)=129140163`

Explanation:

`a_n=a_1(r)^(n-1)\\\\a_(18)=1(3)^(18-1)\\\\a_(18)=3^(17)\\\\a_(18)=129140163`