伯努利悖论：看看以下的推导错了吗？问题出在哪？

$$
\begin{aligned}
\operatorname{Ln}(-z)^2 & =\operatorname{Ln} z^2 \\
\operatorname{Ln}[(-z)(-z)] & =\operatorname{Ln}(z z) \\
\operatorname{Ln}(-z)+\operatorname{Ln}(-z) & =\operatorname{Ln} z+\operatorname{Ln} z \\
2 \operatorname{Ln}(-z) & =2 \operatorname{Ln}(z) \\
\operatorname{Ln}(-z) & =\operatorname{Ln}(z) .
\end{aligned}
$$