[Tex/LaTex] Reducing font size in equation without affecting line spacing

equationsfontsizeline-spacing

I need to reduce the font size in some of my equations. A have already found the same question here, but the highest rated answer — putting \footnotesize before and \normalsize after the equation — is obviously not correct as demonstrated by the following MWE:

\documentclass{article}
\usepackage[TS1,T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}

\begin{document}

This is text of the first paragraph before the equation with correct
line spacing. This is text of the first paragraph before the equation
with correct line spacing.
\begin{equation}
e^{i\pi} - 1 = 0
\end{equation}
This is text of the first paragraph after the equation with correct
line spacing. This is text of the first paragraph after the equation
with correct line spacing.

This is text of the second paragraph before the equation with wrong
line spacing. This is text of the second paragraph before the
equation with wrong line spacing.
\scriptsize\begin{equation}
e^{i\pi} - 1 = 0
\end{equation}\normalsize
This is text of the second paragraph after the equation with correct
line spacing. This is text of the second paragraph after the equation
with correct line spacing.
\end{document}

The problem is that the line spacing of the text directly before the becomes to narrow.

Best Answer

You can use the medsize environment, from nccmath, which displays formulae in about 80 % of \displaystyle. This package also defines the \medmath, \mfrac, \mbinom, \medop and \medint commands.

\documentclass{article}
\usepackage[TS1,T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}
\usepackage{nccmath}

\begin{document}

This is text of the first paragraph before the equation with correct
line spacing. This is text of the first paragraph before the equation
with correct line spacing.
\begin{equation}
  e^{iπ} - 1 = 0
\end{equation}
This is text of the first paragraph after the equation with correct
line spacing. This is text of the first paragraph after the equation
with correct line spacing.

This is text of the second paragraph before the equation with wrong
line spacing. This is text of the second paragraph before the
equation with wrong line spacing.
{\scriptsize\begin{equation}
  e^{iπ} - 1 = 0
\end{equation}}\normalsize
This is text of the second paragraph after the equation with correct
line spacing. This is text of the second paragraph after the equation
with correct line spacing.

This is text of the third paragraph before the equation with correct
line spacing. This is text of the third paragraph before the
equation with correct line spacing.
\begin{equation}\begin{medsize}
    e^{iπ} - 1 = 0
  \end{medsize}\end{equation}
This is text of the thirdd paragraph after the equation with correct
line spacing. This is text of the third paragraph after the equation
with correct line spacing.
\end{document}

enter image description here

Related Question