Question

Como determina o 8° termo da P.G com (1/243,1/81,1/27,...)

Answer 1

Bom dia Gisllany!

Solução!

$q= \dfrac{a2}{a1} \\\\\ q= \dfrac{1}{ \dfrac{81}{ \dfrac{1}{243} } } \\\\\\ q= \dfrac{1}{81}\times \dfrac{243}{1}\\\\\\ q= \dfrac{243}{81}\\\\\ q=3$

Formula da P.G

$an=a1.q^{n-1} \\\\\ a_{8}= \dfrac{1}{243}.3^{8-1}\\\\\ a_{8}= \dfrac{1}{243}.3^{7}\\\\\ a_{8}= \dfrac{1}{243}.2187\\\\\ a_{8}= \dfrac{2187}{243} \\\\\ a_{8}=9$

$\boxed{Resposta:a_{8}=9}$

Bom dia!
Bons estudos!