Q=3

s5=484

b1?

b5?

b3=0,024

s3=0,504

b1?

q?

1) b1=s (q-1) / (q^5-1) = 484*2/242=4

b5=b1q^4=4*81=324

2) b1=s (q-1) / (q^3-1) = s / (q^2+q+1)

b3=b1q^2⇒b1=b3/q^2

s / (q^2+q+1) = b3/q^2

21 / (q^2+q+1) = 1/q²

21q²=q²+q+1

20q²-q-1=0

D=1+80=81

q1 = (1-9) / 40=-1/5⇒b1=0,024/0,04=0,6

q2 = (1+9) / 40=1/4⇒b1=0,024:1/16=0,384