Odpowiedzi

2010-04-11T22:52:33+02:00
Sn = n(n+2)
a1 = S1 = 1*(1+2) = 1*3 = 3
S2 = 2*(2+2) = 2*4 = 8
S2 = a1+a2
a2 = S2−a1 a2 = 8−3 = 5
r = a2−a1 r = 5−3 = 2
a1 = 3
r = 2.

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