Question

. Na PG ( 8/3, - 8/9, 8/27 , - 8/81, .....) calcular a razão q da
PG e o valor do termo na posição 9, ou seja a9​

Answer 1

$q = \frac{a2}{a1}$

$q = \frac{ \frac{ - 8}{9} }{ \frac{8}{3} }$

$q = \frac{ - 8}{9} . \frac{3}{8} = \frac{ - 24}{72} = \frac{ - 6}{18} = \frac{ - 1}{3}$

$a9 = a1.q ^{8}$

$a9 = \frac{8}{3} .( \frac{ - 1}{3})^{8}$

$a9 = \frac{8}{3}.( \frac{ 1}{6561} )$

$a9 = \frac{</strong><strong> 8}{19683}$