Answer:
It is 1. A(n) =3(3^n-1)
Step-by-step explanation:
It is a geometric progression
General recursive formular:
[tex]a_{n} = a( {r}^{n-1} )[/tex]
a » first term, a = 3
r » common difference, r = 9 ÷ 3 = 3
n » number of terms
[tex]A(n) = 3( {3}^{n-1} )[/tex]
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further more:
[tex]A(n) = {3}^{(n)} [/tex]
