From 151588bcb60e7f5c711abcbdcc6c6c6a7bfd6b42 Mon Sep 17 00:00:00 2001 From: ceciliachan1979 <75919064+ceciliachan1979@users.noreply.github.com> Date: Tue, 5 Mar 2024 06:39:52 -0800 Subject: [PATCH] Fix the same problem again --- Books/BabyRudin/Chapter03/ex06.cecilia.tex | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/Books/BabyRudin/Chapter03/ex06.cecilia.tex b/Books/BabyRudin/Chapter03/ex06.cecilia.tex index 6c8acae..5e8dec4 100644 --- a/Books/BabyRudin/Chapter03/ex06.cecilia.tex +++ b/Books/BabyRudin/Chapter03/ex06.cecilia.tex @@ -49,12 +49,12 @@ \subsubsection*{Part d} \begin{eqnarray*} & & \frac{\frac{1}{|z^{n+1}| - 1}}{\frac{1}{|z^n| - 1}} \\ &=& \frac{|z^n| - 1}{|z^{n+1}| - 1} \\ - &<& \frac{|z^n| - 1}{|z^{n+1}|} \\ - &=& \frac{|z^n|}{|z^{n+1}|} - \frac{1}{|z^{n+1}|} \\ - &=& \frac{1}{|z|} - \frac{1}{|z^{n+1}|} + &<& \frac{|z^n| - 1}{|z^{n+1}| - |z|} \\ + &=& \frac{1}{|z|} \\ + &<& 1 \end{eqnarray*} -So, as $ n $ tends to $ \infty $, the sequence $ \frac{a_{n+1}}{a_n} $ is upper bounded by a sequence that tends to $ \frac{1}{|z|} < 1 $, so the sequence converges by the ratio test. +Therefore the $ \limsup \left| \frac{\frac{1}{|z^{n+1}| - 1}}{\frac{1}{|z^n| - 1}} \right| < 1$. On the other hand, if $ |z| \ge 1 $.