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#