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Fieprogresia geometria b3=6, b7=54. Calculati b1

Răspuns :

bn = b1 x q^(n-1)
b3 = b1 x q^2 = 6
b7 = b1 x q^6 = 54
Impartim cele 2 relatii:
(b1 x q^6)/(b1 x q^2) = 54/6
q^4 = 9
q = radical din 3

Atunci b1 x q^2 = 6
b1 x 3 = 6
b1 = 2
b7=b3 * q^4
q^4=54:6
q^4=9 => q^2=√9 => q=√3
b3=b1*q^2
6=b1* √3^2
b1=6:3=2