Question

obetenha o oitavo termo da P.G (1,3,9,...)?

Answer 1

$\begin{matrix}P.G.=(1,3,9,...)\\\\\\a_n=a_1\cdot q^{n-1}\\\\a_8=a_1\cdot q^{8-1}\\\\a_8=1\cdot3^7\\\\\boxed{a_8=2187}\end{matrix}\qquad\qquad\begin{matrix}&q=\dfrac{a_n}{a_{n-1}},\ \ p/:\ n\ge2,\ n\in\mathbb{N}&\\\\&q=\dfrac{a_2}{a_{2-1}}\ \to\ q=\dfrac{a_2}{a_1}\ \to\ q=\dfrac{3}{1}\ \to q=3&\end{matrix}$

Answer 2

a8=2187 pois o razao é tres logo se multiplicar o ultimo termo por tres e assim suscessivamente dara o resultado de 2187