What is the 9th term of the geometric sequence 3, 9, 27,...?

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Answer 1 · 2018-03-04T09:31:35

I get $19683$ .

The sequence is:

$3,9,27,...$

or we can write it as

$3^1,3^2,3^3,...$

So, the pattern is just powers of $3$ .

I see immediately that if $n$ is the term in the sequence, it is given by $3^n,ninNN$ .

So, the sequence is

$a_n=3^n$ , where $a_n$ is the $n^("th")$ term.

Therefore, the ninth term will be

$a_9=3^9$

$=19683$