BBy Bot
May 31'24

Exercise

[math] \newcommand{\indexmark}[1]{#1\markboth{#1}{#1}} \newcommand{\red}[1]{\textcolor{red}{#1}} \newcommand{\NOTE}[1]{$^{\textcolor{red}\clubsuit}$\marginpar{\setstretch{0.5}$^{\scriptscriptstyle\textcolor{red}\clubsuit}$\textcolor{blue}{\bf\tiny #1}}} \newcommand\xoverline[2][0.75]{% \sbox{\myboxA}{$\m@th#2$}% \setbox\myboxB\null% Phantom box \ht\myboxB=\ht\myboxA% \dp\myboxB=\dp\myboxA% \wd\myboxB=#1\wd\myboxA% Scale phantom \sbox\myboxB{$\m@th\overline{\copy\myboxB}$}% Overlined phantom \setlength\mylenA{\the\wd\myboxA}% calc width diff \addtolength\mylenA{-\the\wd\myboxB}% \ifdim\wd\myboxB\lt\wd\myboxA% \rlap{\hskip 0.35\mylenA\usebox\myboxB}{\usebox\myboxA}% \else \hskip -0.5\mylenA\rlap{\usebox\myboxA}{\hskip 0.5\mylenA\usebox\myboxB}% \fi} \newcommand{\smallfrac}[2]{\scalebox{1.35}{\ensuremath{\frac{#1}{#2}}}} \newcommand{\medfrac}[2]{\scalebox{1.2}{\ensuremath{\frac{#1}{#2}}}} \newcommand{\textfrac}[2]{{\textstyle\ensuremath{\frac{#1}{#2}}}} \newcommand{\nsum}[1][1.4]{% only for \displaystyle \mathop{% \raisebox {-#1\depthofsumsign+1\depthofsumsign} \newcommand{\tr}{\operatorname{tr}} \newcommand{\e}{\operatorname{e}} \newcommand{\B}{\operatorname{B}} \newcommand{\Bbar}{\xoverline[0.75]{\operatorname{B}}} \newcommand{\pr}{\operatorname{pr}} \newcommand{\dd}{\operatorname{d}\hspace{-1pt}} \newcommand{\E}{\operatorname{E}} \newcommand{\V}{\operatorname{V}} \newcommand{\Cov}{\operatorname{Cov}} \newcommand{\Bigsum}[2]{\ensuremath{\mathop{\textstyle\sum}_{#1}^{#2}}} \newcommand{\ran}{\operatorname{ran}} \newcommand{\card}{\#} \newcommand{\Conv}{\mathop{\scalebox{1.1}{\raisebox{-0.08ex}{$\ast$}}}}% \usepackage{pgfplots} \newcommand{\filledsquare}{\begin{picture}(0,0)(0,0)\put(-4,1.4){$\scriptscriptstyle\text{\ding{110}}$}\end{picture}\hspace{2pt}} \newcommand{\mathds}{\mathbb}[/math]

A weak spot of our method above is that the point that we start with could lie somewhere far away from both of the two annuli. Think of ways to improve on this.