Can someone help with this?

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1 Answer
May 10, 2018

Answer is b

Explanation:

Because geometric sequence has the formula as
a_n=a_0r^(n-1) where a_0 is the first term and r is the ratio.

In our case a_0=1

r is the ratio which can be obtained a_2/a_1=3 and in general

a_n/a_(n-1)=r So in your question it is 3/1So r=3
While n is the number of term
If they would have said T9
This means n=9
Thus your term is a_n=1*3^(n-1)