Question

Any help? I'm stuck. Find the next three terms in the geometric sequence and write the explicit function used to find the "nth" term. -1, 1, -1, 1, ...

Answer 1

the common ratio, r = 1 / -1 = -1

First term, a = -1

`\begin{gathered} U_n=ar^(n-1) \\ \Rightarrow U_n=(-1)(-1)^(n-1)=(-1)^(n-1+1) \\ \Rightarrow U_n=(-1)^n \end{gathered}`