(5) If $z_{1}, z_{2}, \cdots, z_{n} \in \mathbf{C},\left|z_{1}\right|=\left|z_{2}\right|=\cdots=\left|z_{n}\right|=r \neq 0, T_{s}$ represents the sum of all possible products of $s$ numbers taken from these $n$ numbers. Find: If $T_{n-s} \neq 0$, then $\left|\frac{T_{s}}{T_{n-s}}\right|=$ $\qquad$ . (Express in terms of $r$)
(Answer: $r^{2 s-n}$ )