Найдите сумму первых шести членов геометрической прогрессии b1=1 b4=8
B4 = b1*q^3 = q^3 = 8 q^3 = 8 q^3 = 2^3 q = 2 S6 = (b1*(1 - q^6))/( 1 - q) = (1 - q^6)/(1 - q) = = ( 1 - 2^6) / (1 - 2) = (2^6 - 1)/ (2 - 1) = 2^6 - 1 = 63