Найти S6 если b1 = 4 q=1/2

Question

Найти S6 если b1 = 4 q=1/2

Answer 1

S = (b1*(1-q^n))/(1-q)
S6=(4*(1-(1/2)^6)/(1-1/2) = (4*(1-1/64))/(1/2) = 4*(63/64)/(1/2) = (63/16)/(1/2) = 63/8