Closed end problem

Question

How can we make the tip of the closed square root symbol better?

\documentclass{standalone}
\usepackage{amsmath}
\usepackage{letltxmacro}
\LetLtxMacro{\OldSqrt}{\sqrt}
\newcommand{\ClosedSqrt}[1][\hphantom{3}]{\def\DHLindex{#1}\mathpalette\DHLhksqrt}
\makeatletter
    \newcommand\bold@name{bold}
    \def\DHLhksqrt#1#2{%
        \setbox0=\hbox{$#1\OldSqrt{#2,}$}\dimen0=\ht0\relax%
        \advance\dimen0-0.25\ht0\relax% size of the added box is still 0.2 times ht0
        \setbox2=\hbox{\vrule height\ht0 depth -\dimen0}%
        {\hbox{$#1\expandafter\OldSqrt\expandafter[\DHLindex]{#2,}$}
        \lower\ifx\math@version\bold@name0.6pt\else0.4pt\fi\box2}
    }
    % root index positioning and added space at the end, mostly noticeable in inline math mode
    \renewcommand{\sqrt}[2][\ ]{\ClosedSqrt[\leftroot{-2}\uproot{1}#1]{#2}\kern0.1em} 
\makeatother
\begin{document}
$\sqrt{2}$
\end{document}

You can't improve an ugly symbol… – egreg Oct 12 '21 at 12:22 — egreg, Oct 12 '21 at 12:22
Please define "better" in the present context? – Mico Oct 12 '21 at 12:37 — Mico, Oct 12 '21 at 12:37

score 2 · Accepted Answer · answered Oct 12 '21 at 13:24

Do you want a round cap? It can be done, but the symbol is really ugly and useless.

\documentclass{article}
\usepackage{amsmath}
\usepackage{letltxmacro}
\usepackage{pict2e}
\DeclareFontShape{OMX}{cmex}{b}{n}{<->cmexb10}{}
\SetSymbolFont{largesymbols}{bold}{OMX}{cmex}{b}{n}
\LetLtxMacro{\OldSqrt}{\sqrt}
\newcommand{\ClosedSqrt}[1][\hphantom{3}]{\def\DHLindex{#1}\mathpalette\DHLhksqrt}
\makeatletter
\newcommand\bold@name{bold}
\def\DHLhksqrt#1#2{%
  \setbox0=\hbox{$#1\OldSqrt{#2,}$}\dimen0=\ht0\relax%
  \advance\dimen0-0.25\ht0\relax% size of the added box is still 0.2 times ht0
  \setbox2=\hbox{\vrule height\ht0 depth -\dimen0}%
  \begingroup
  \hbox{$#1\expandafter\OldSqrt\expandafter[\DHLindex]{#2,}$}%
  \dimen2=\fontdimen8
    \ifx#1\displaystyle\textfont\else
    \ifx#1\textstyle\textfont\else
    \ifx#1\scriptstyle\scriptfont\else
    \scriptscriptfont\fi\fi\fi 3
  \lower1.5\dimen2\hbox{\closer@{#1}}%
  \endgroup
}
% root index positioning and added space at the end, mostly noticeable in inline math mode
\renewcommand{\sqrt}[2][\ ]{\ClosedSqrt[\leftroot{-2}\uproot{1}#1]{#2}\kern0.1em}
\newcommand\closer@[1]{%
  \raisebox{\dimen0}{%
    \kern-0.5\dimen2
    \unitlength=\dimexpr\ht0-\dimen0\relax
    \begin{picture}(0,1)
    \linethickness{\dimen2}%
    \roundcap
    \Line(0,0)(0,0.4)
    \buttcap
    \Line(0,0.3)(0,1)
    \end{picture}%
  }%
}
\makeatother
\begin{document}
[
\sqrt{2}+\sqrt[3]{\frac{1}{2}}-\scriptstyle\sqrt{2}
]
\boldmath
[
\sqrt{2}+\sqrt[3]{\frac{1}{2}}-\scriptstyle\sqrt{2}
]
\end{document}

Excuse for this comment Prof.. But the question is it similar to this? https://tex.stackexchange.com/questions/29834/closed-square-root-symbol?rq=1 — Sebastiano, Oct 12 '21 at 22:18
@Sebastiano Yes, but the problem is to change the end of the vinculum to be round, I have guessed. — egreg, Oct 12 '21 at 22:39
Surely...in fact I have upvoted you :-). Just a succesive comment: but the 3 (also in bold) it is very closer to the sqrt. — Sebastiano, Oct 12 '21 at 22:44
@Sebastiano I didn't change the setting of \uproot ad \leftroot. I consider the symbol bad anyway. — egreg, Oct 12 '21 at 22:53

Closed end problem

1 Answers1