Question

What are the explicit equation and domain for a geometric sequence with a first term of 2 and a second term of −8? an = 2(−8)n − 1; all integers where n ≥ 1 an = 2(−8)n − 1; all integers where n ≥ 0 an = 2(−4)n − 1; all integers where n ≥ 0 an = 2(−4)n − 1; all integers where n ≥ 1

Answer 1

Hello,

The question is
"What are the explicit equation and domain for a geometric sequence with a first term of 2 and a second term of −8?"

It is a geometric sequence =>U(2)=U(1)*r==>-8=2*r ==>r=-4

U(1)=2=2*(-4)^0
U(2)=-8=2*(-4)=2*(-4)^1
U(3)=32=-8*(-4)=2*(-4)(-4)=2*(-4)^2
U(4)=-128=32*(-4)=2*(-4)^3
...
U(n)=2*(-4)^(n-1) where n>=1.

Answer C