[pstricks] How to show a specific point of a function's curve?

[Herbert Voss]

Am 23.01.2011 19:11, schrieb Denis Bitouzé:

> What would be the best way to show the point of the curve (with a qdisk
> on the point and two parallel lines for its x- and y-values) just by
> specifying its x-value?

\documentclass{article}
\usepackage{pstricks-add}
\psset{algebraic}
\begin{document}

\begin{psgraph}(0,0)(5,3){6cm}{!}
  \psplot{0}{5}{x^2/10}
  \qdisk(*3 {x^2/10}){2pt}% or \pnode(*3 {x^2/10}){Fx}
  \psline(3,0)(*3 {x^2/10})(0,0|*3 {x^2/10})
\end{psgraph}

\end{document}

With the node definition it is
  \qdisk(Fx){2pt}
  \psline(3,0)(Fx)(0,0|Fx)

Herbert