A(n)=-5*2^n-1 i dont know the geometric sequences i need the first, fourth and eighth terms of the sequence

1 answer:

7 0

$\bf A(n)=5\cdot 2^{n-1}\qquad \qquad 
\begin{array}{llll}
4th~term\\
5\cdot 2^{4-1}\implies 5\cdot 2^3\implies 5\cdot 8\implies 40
\\\\\\
8th~term\\
5\cdot 2^{8-1}\implies 5\cdot 2^7\implies 5\cdot 128\implies 640
\end{array}$

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