Suppose \(0 \lt c \lt 1\text{.}\) Then
\begin{equation*}
c \gt c^2 \gt c^3 \gt
\cdots
\end{equation*}
\begin{equation*}
c^2 , c^3 , c^4,
\ldots
\end{equation*}
converges to \(cL\text{.}\) However, this sequence is just the original sequence with the first term dropped, so by the uniqueness of limits, \(cL = L\text{.}\) But \(0 \lt c \lt 1\text{,}\) so \(L\) must be \(0\text{.}\)
If
\(c \gt 1\text{,}\) then
\(0 \lt 1/c \lt 1\text{,}\) so
\(1/c^n \to
0^+\) and hence
\(c^n \to +\infty\text{.}\)