\documentclass{article}
\usepackage{tikz}
\usepackage{pgfplots}
\usepackage{verbatim}
\usepackage[active,tightpage, floats]{preview}
\setlength\PreviewBorder{5pt}%
\begin{comment}
\end{comment}
\begin{document}
\begin{figure}[h!]% H h! h - тут; t - вверху страницы; b - внизу страницы
\begin{tikzpicture}
\begin{axis}
\addplot [solid, fill=blue, draw = blue, thick] coordinates {(0,0) (0.5,1) (1,2) (1.3,1.7) (1.6,2.1) (1.9,1) (0,0)} \closedcycle;
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}