Question

Записать формолу n-го члена b1=6, q=-2, Найти: b5=?; s5=?

Answer 1

b₁ = 6,  q = -2
b₅ = b₁q⁴ = 6*(-2)⁴ = 6*16 = 96
S₅ = b₁(q⁵ -1) / (q -1) = 6*(-32 -1)/(-2 -1) = 2*33 = 66
bn = b₁q^(n-1)