# How add line spacing to a footnote with equations?

I need to add some footnotes that explain the equations used to obtain certain results. However, one is a fraction with a floor function and extends to the upper and lower lines. How do I add space between the lines where equation of footnote 2 is touching equation of footnote 3 without affection the normal linespread of all other footnotes?

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{mathtools}
\DeclarePairedDelimiter\ceil{\lceil}{\rceil}
\DeclarePairedDelimiter\floor{\lfloor}{\rfloor}

\begin{document}
First equation\footnote{my footnote
$\mathrm{NMI}=(L+R)-P$}.
Then second equation\footnote{Another footnote
$\mathrm{NMPI}=\floor*{\dfrac{(L+1)(R+1)}{P+1}-1}$}
Then third equation \footnote{Long footnote longer explanation
$\mathrm{IL}=\dfrac{L \times R }{P}$}
Final footnote with equation\footnote{This is the last footnote
but it has no equations.}
\end{document}


• Why not use $\mathrm{NMPI} = \floor*{(L + 1)(R + 1) / (P + 1) - 1}$?
– Werner
Nov 14 '19 at 2:09
• I fail to reproduce the output but if you replace $\mathrm{NMPI}=\floor*{\dfrac{(L+1)(R+1)}{P+1}-1}$ by $\vphantom{\begin{array}{c}{}\\[1em]{}\end{array}}\mathrm{NMPI}=\floor*{\dfrac{(L+1)(R+1)}{P+1}-1}$ the spacing will increase. Of course, you can change 1em to your liking.
– user194703
Nov 14 '19 at 2:49

You could simply add a \vspace{1ex} command inside the footnote.

Then second equation\footnote{Another footnote
$\mathrm{NMPI}=\floor*{\dfrac{(L+1)(R+1)}{P+1}-1}$\vspace{1ex}}

• Thanks. Simple and working as I needed it. Nov 14 '19 at 16:37

Using a _{\mathstrut} can add some depth to the expression not to interfere with the line below.

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{mathtools}
\DeclarePairedDelimiter\ceil{\lceil}{\rceil}
\DeclarePairedDelimiter\floor{\lfloor}{\rfloor}

\begin{document}
First equation\footnote{my footnote
$\mathrm{NMI}=(L+R)-P$}.
Then second equation\footnote{Another footnote
$\mathrm{NMPI}=\floor*{\frac{(L+1)(R+1)}{P+1}-1}_{\mathstrut}$}
Then third equation \footnote{Last footnote and longer explanation
$\mathrm{IL}=\frac{L \times R }{P}$}
Final footnote with equation\footnote{This is the last footnote
but it has no equations.}
\end{document}


Another (and my own recommended) option is to use manually sized fine tuned delimiters instead of the too big \left and \right. Also, I don't think \dfrac is a good choice for a footnote.

$\mathrm{NMPI}=\bigl\lfloor\frac{(L+1)(R+1)}{P+1}-1\bigr\rfloor$