b₄=b₁*q³=625 *(-1/5)³=-625/125= -5
S₄=b₁(1-q^n) /(1-q)=625(1-1/625) /(1+1/5)=520
в₄=625*q^(4-1) в₄=625*(-1/5)^3=625* (-1/125)=-5 B₅=(-5)*(-1/5)=1 S₅= (B₅q-b1)/q-1; S₅=(-1/5-625)/(-1/5-1)=(-626.2)/(-1.2)=521
b₄=b₁*q³=625 *(-1/5)³=-625/125= -5
S₄=b₁(1-q^n) /(1-q)=625(1-1/625) /(1+1/5)=520
в₄=625*q^(4-1)
в₄=625*(-1/5)^3=625* (-1/125)=-5 B₅=(-5)*(-1/5)=1
S₅= (B₅q-b1)/q-1; S₅=(-1/5-625)/(-1/5-1)=(-626.2)/(-1.2)=521