\documentclass{article}
\usepackage{iftex}
\usepackage{ifthen}
\usepackage{epsfig}
\usepackage[utf8]{inputenc}
\usepackage{xcolor}
\ifPDFTeX
\usepackage{newunicodechar}
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\pagestyle{empty}
\begin{document}
$\rho = \frac{a (1-e^2)}{(1-e^2\sin^2 lon)^{3/2}}
$
\pagebreak

$\nu = \frac{a}{(1-e^2\sin^2 lon)^{1/2}}
$
\pagebreak

$r = \frac{a (1-e^2)^{1/2}}{(1-e^2\sin^2 lon)}
$
\pagebreak

\[ a = {\bf x}^T  {\bf y} \]
\pagebreak

\[ a = ||{\bf x}||_2 \]
\pagebreak

\[ a = ||{\bf x}||_1 \]
\pagebreak

\[ a = ||{\bf x}||_\infty \]
\pagebreak

\[ {\bf z} = a{\bf x} + b{\bf y} \]
\pagebreak

\[ {\bf y} = {\bf x} \]
\pagebreak

\[ {\bf C} = a {\bf A} + {\bf B} \]
\pagebreak

\[ {\bf C} = {\bf A}{\bf B} \]
\pagebreak

\[ {\bf z} = a{\bf x} + {\bf y} \]
\pagebreak

\[Ss \frac{\partial h}{\partial t} = \nabla {\bf K} \nabla h + q \]
\pagebreak

\[\frac{\partial c_g}{\partial t} R = \nabla \cdot ({\bf D} \nabla c_g -
{\bf u} c_g) + \sigma + \frac{q}{n_f}(c_g - c_in) \]
\pagebreak

\end{document}
