1) b1=-32, q=1,2 найти b7=? 2) b1=2, q=6 найти S6=? 3) S9=?, b2=0,04, b4=0,16 4) найти b1=? если q=3, S4=560

1) b7=b1*q^6=-32* (1/2)^6 = -32*1/64 =-1/22)Sn = b1*(1-q^n)/(1-q) S6 = 2*(1-6^6)/(1-6) = 2*(1-46656)/(-5)= 2*(-46655)/(-5) = 18662.3)b4 = b2*q^2 q^2 = b4/b2 = 0.16/0.04 = 4, q = ± √4 = ±2b2 = b1*q, b1=b2/qЕсли q = 2, b1=0.04/2 = 0.02; S9 = 0.02*(1-2^9)/(1-2) = 0.02*(1-512)/(-1) = 0.02*511 = 10.22Если q = -2, b1=0.04/(-2) = -0.02; S9 = -0.02*(1+2^9)/(1+2) = -0.02*513/3 = -3.42 4) S4 = b1*(1 - q^4)/(1-q) 560 = b1*(1-3^4)/(1-3) 560=b1*(-80)/(-2) 560 = b1*40 b1=560/40 b1= 14.