\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{polski}
\usepackage{amsmath}
\usepackage{tikz}
\usepackage{pgfplots}

\begin{document}

\[
x\mapsto x^2-2x+3\
\]
\begin{tikzpicture}
\begin{axis}
\addplot{(x^2-2*x+3)};
\end{axis}	content...
\end{tikzpicture}
\\

\[
x\mapsto \cos 2x\
\]
\begin{tikzpicture}
\begin{axis}
\addplot{(cos(2*x))};
\end{axis}	content...
\end{tikzpicture}
\\

\[
x\mapsto\sin \tfrac{1}{x}\
\]
\begin{tikzpicture}
\begin{axis}
\addplot{(sin(1/x))};
\end{axis}	content...
\end{tikzpicture}
\\

\[
(x,y)\mapsto x^2+y^2\
\]
\begin{tikzpicture}
\begin{axis}
\addplot3{(x^2+y^2)};
\end{axis}	content...
\end{tikzpicture}
\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ 

\[
(x,y)\mapsto x^2-y^2 + 2 x y ^2+1\
\]
\begin{tikzpicture}
\begin{axis}
\addplot3{(x^2-y^2+2*x*y^2+1)};
\end{axis}	content...
\end{tikzpicture}
\\


\end{document}