Question

Помогите 4 задание !!!!!!!!!!!!

Answer 1

bₓ=b₁qˣ⁻¹    b₁=1/4   b₂=(1/4)(-1/2)=-1/8   b₃=(1/4)(-1/2)²=(1/4)(1/4)=1/16
b₄=(1/4)(-1/2)³=(1/4)(-1/8)=-1/32
Sₓ=b₁(qˣ-1)/(q-1)        S₇=(1/4)((-1/2)⁷-1)/(-1/2-1)=(1/4)(-1/128-1)/(-3/2)=
(1/4)(-129/128)/(-3/2)=43/256