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What is the recursive formula for finding the nth term of the given geometric sequence?13,-39,117,-351,...

What is the recursive formula for finding the nth term of the given geometric sequence-example-1
User Casanova
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1 Answer

4 votes

Solution:

Given:


13,-39,117,-351,...

The recursive formula of a geometric sequence is given by;


a_n=a_(n-1)\cdot r

The common ratio is;


\begin{gathered} r=(-39)/(13)=(117)/(-39) \\ r=-3 \end{gathered}

The first term is;


a_1=13

Therefore, the recursive formula is;


\begin{gathered} a_n=a_(n-1)(-3) \\ a_n=-3(a_(n-1)) \end{gathered}

User Chuleta
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