problem with text formatting \ itemize

Question

I looked for a command to improve the equation item and I met this one.

\usepackage{amsmath}
newcommand{\itemEq}[1]{%
         \begingroup%
         \setlength{\abovedisplayskip}{0pt}%
         \setlength{\belowdisplayskip}{0pt}%
         \parbox[c]{\linewidth}{\begin{flalign}#1&&\end{flalign}}%
         \endgroup}

working with the command I noticed that it has problems recalling the foonotes but also with the format of the text, such as in this case:

\begin{itemize}

\item[d)]\itemEq{\Dtot{\ui}{t}=\Dpar{\ui}{t}+\sum_{j=1}^{3}\Dpar{\ui}{x_j}\uj = \uit+\ui\cdot\uij:\text{Derivata Lagrangiana  della componente i-esima della velocità}}  

\end{itemize}

the text is very long and I can not go to the next line

-----------------------UPDATE---------------------------

I found the solution :

\item[d)]\itemEq{\Dtot{\ui}{t}=\Dpar{\ui}{t}+\sum_{j=1}^{3}\Dpar{\ui}{x_j}\uj = \uit+\ui\cdot\uij:\text{\parbox{5cm}{Derivata Lagrangiana  della componente i-esima della velocità}}}

@Bernard Because it seemed appropriate. but I do not think so. — Antonio, Nov 07 '18 at 21:32
What so you try to achieve? An equation in \displaystyle, and some explanation afterwards, beginning on the same line? — Bernard, Nov 07 '18 at 21:47

score 2 · Answer 1 · answered Nov 07 '18 at 23:18

I can propose this, based on tabularx. Not having your macros, I loaded the diffcoeff package to simplify typing of derivatives.

\documentclass[italian]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage{ragged2e}
\usepackage[showframe]{geometry}
\usepackage{amsmath, diffcoeff}
\usepackage{enumitem}
\usepackage{tabularx}

\begin{document}

\begin{enumerate}[label=\alph*), start=4]
\item
\begin{tabularx}{\linewidth}{>{$\displaystyle}c<{$}>{\RaggedRight\arraybackslash}X@{}|}
\Diff{u_i}{t}=\diffp{u_i}{t}+∑_{j=1}^{3}\diffp{u_i}{x_j}u_j = u_{i, t} +u_i \cdot u_{i, j} :
& Derivata Lagrangiana della componente i-esima della velocità.
\end{tabularx}
\end{enumerate}

\end{document}

score 1 · Accepted Answer · answered Nov 07 '18 at 23:36

You can measure the equation and set the text in the remaining space with some clearance. But my preference would be to state the description and then display the equation.

\documentclass[a4paper]{article}
\usepackage[T1]{fontenc}
\usepackage[italian]{babel}
\usepackage{amsmath}
\usepackage{enumitem}

\newsavebox{\eqdescbox}

\newcommand{\eqdesc}[2]{%
  \sbox{\eqdescbox}{$\displaystyle #1$}%
  \usebox{\eqdescbox}\hfill
  \parbox[t]{\dimexpr\linewidth-2em-\wd\eqdescbox}{\raggedright #2}%
}

\newcommand{\Dtot}[2]{\frac{D#1}{D#2}}
\newcommand{\Dpar}[2]{\frac{\partial#1}{\partial#2}}

\begin{document}

\begin{enumerate}[label=\alph*)]

\item \eqdesc{
  \Dtot{u_i}{t}=\Dpar{u_i}{t}+\sum_{j=1}^{3}\Dpar{u_i}{x_j}u_j =
  u_it+u_i\cdot u_{ij}
}{Derivata Lagrangiana  della componente $i$-esima della velocità}

\item Derivata Lagrangiana  della componente $i$-esima della velocità
\begin{equation*}
  \Dtot{u_i}{t}=\Dpar{u_i}{t}+\sum_{j=1}^{3}\Dpar{u_i}{x_j}u_j =
  u_it+u_i\cdot u_{ij}
\end{equation*}

\end{enumerate}

\end{document}

I don't think you gain too much by typing \ui over u_i: it's error prone and forces you to remember too many commands.

I have a problem of displaying the braces and with the subscript: u_i, u_ i, ij, i, u_ {j, ij} ... etc. etc. I was forced to write the synthetic commands, equations. In TeXStudio I did not find a way to have a different color in the brackets, I often find the code boring. — Antonio, Nov 08 '18 at 07:01

problem with text formatting \ itemize

2 Answers2