B1=1/3 q=1/3 Bn=1/6561 n-? Sn-?

Question

B1=1/3 q=1/3 Bn=1/6561 n-? Sn-?

Answer 1

Т.к |q|<1, то Sn=b1/1-q<br>bn=b1*q^n
1/6561=(1/3)*(1/3)^n
1/3^8=1/3^(n+1)
3^8=3^(n+1)
n+1=8; n=7
Sn=(1/3)/(2/3)=1/2=0,5
Ответ: n=7; Sn=0,5