[pstricks] \psplotTangent

[Cyrille Piatecki]

Dear all,

I don't understand why the tangent is not shown on my computer.

\documentclass[11pt]{article}
\usepackage{pstricks, pstricks-add}
\pagestyle{empty}
\begin{document}


\begin{center}
\begin{pspicture}(-3,-2.)(7.5,7.)
%\psgrid
\psline{<->}(0,6.4)(0,1)(7.4,1)
\psset{xunit=2cm,yunit=2cm}
\pscustom[fillstyle=slope,slopebegin=white,slopeend=skyblue]{
\psplot[algebraic,linewidth=1.2pt]{0}{3.58}{3-.1945*x^2}
\lineto(0,.5)
}
\psplot[algebraic,linecolor=venetianred]{0}{3.6}{3-.1945*x^2}
\psrotate(1.14, 
1.2475){180}{\psplot[algebraic,linecolor=venetianred]{0}{3.52}{3-.1945*x^2}
\psplotTangent{1.5}{1}{3-.1945*x^2}
\pscustom[fillstyle=slope,slopebegin=white,slopeend=skyblue,linestyle=none]{
\psplot[algebraic,linewidth=1.2pt]{0}{3.58}{3-.1945*x^2}
\lineto(0,.5)
}}
\psrotate(1.14, 
1.25){180}{\psplot[algebraic,linecolor=venetianred,linewidth=1.2pt]{0}{3.575}{3-.1945*x^2}}
\pspolygon[fillstyle=slope,slopebegin=skyblue,slopeend=white](0,0.5)(0,1.975)(2.275,1.975)(2.275,0.5)
\psplotTangent*{2.25}{2cm}{3-.1945*x^2}
\psset{origin={0.,.5},xunit=.5cm,yunit=.5cm}
\psplot[linecolor=turquoisedark,linewidth=2pt,linestyle=solid,algebraic]{0}{9.1}{(3.333*x)/((0.238*x)+(3))}
\psset{origin={0,0},xunit=1cm,yunit=1cm}
\psline{<->}(0,6.4)(0,1)(7.4,1)
\psplotTangent*{2.25}{2cm}{3-.1945*x^2}
\psline{<->}(4.55,-1.2)(4.55,3.95)(-2.8,3.95)
\end{pspicture}
\end{center}

\end{document}

Thanks

Cyrille Piatecki