Question

determinar o nono termo da pg (81,27,9,...).

Answer 1

81 ------ 1

27 ------ x

      $x = \frac{27}{81}$

      $x = \frac{1}{3}$ (simplificando)

$q = \frac{1}{3}$

$an = a1 . q ^(n-1)$

$a9 = 81 . \frac{1}{3} ^(9-1)$

$a9 = 81 . \frac{1}{3}^8$

$a9 = 0,012345679$