Question

найти n если b1=1/3 q=1/3 bn=1/729 

Answer 1

$b_{n}= b_{1}* q^{n-1}$
$frac{1}{729}= frac{1}{3}* ( frac{1}{3} )^{n-1}$
$frac{1}{243} = ( frac{1}{3} )^{n-1}$
$( frac{1}{3} )^{5}= ( frac{1}{3} )^{n-1}$
n-1 = 5
n = 6
Ответ: 6