Question

срооооочно решите.b3=54 b5=6 Найти:S6

Answer 1

.b3=54 b5=6 Найти:S6
b5/b3=b1q^4/b1q^2=q^2=6/54=1/9
b1=54*9
q=1/3
s6=b1(1-q^6)/(1-q)=54*9(1-1/729)*3/2=2*3*9(728/729)*3/2=728/9
q=-1/3
S6=54*9(1-1/729)*-3/4=-364/9