b(1) = -2
b(n+1) = -2* 1/b(n)
b(2) = 2*1/2 = 1
b(3) = -2*1 = -2
b(4) = 2*1/2 = 1
b(5) = -2/1 = -2
q = b₂ / b₁ = -140 / -175 = 0.8
Формула-b(n) = b₁ * qⁿ⁻¹
b(5) = -175 * 0.8⁴ = -71.68
q = b₂ / b₁ = -64 / -256 = 0.25
Формула-b(n) = b₁ * qⁿ⁻¹
b(5) = -1024 * 0.25⁴ = -4
Формула-S(n) = b₁-b₂*qⁿ⁻¹
\1-q
S(n) = -1024+4*0,25\1-0,25=-1364
Знаменатель прогрессии q = -3
b(7)=-113*
=-113*729=-82377
Знаменатель прогрессии q = 3
S(5) = b₁(q⁵ - 1)/(q - 1) = -7(3⁵ - 1)/(3 - 1) = -7(243 - 1)/2 = -7 · 242/2 = -7 · 121 = -847
q=b₄/b₃ = -96/24 = -4
b₂=b₁*q=1.5 * (-4)= -6