Для геометрической прогрессии (bn) найдите Sn, если: в) b1 = -4, q = ½; n = 13; г) b1 = 4,5, q = 1/3, n = 8.

в) s13 = b1 * (1-q^13)/(1-q) = -4 *(1-1/8192) /(1/2) = -8191*4/(8192*0.5) = -8191/1024 = -8 г) s8 = 4.5 * (1-(1/3)^8)/(2/3) =4.5 * 6560 * 3/ (2 * 6561) = 6.75