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

[Denis Bitouzé]

Le lundi 24/01/11 à 09h19,
Herbert Voss a écrit :

> Am 23.01.2011 19:11, schrieb Denis Bitouz?:
> 
> > What would be the best way to show the point of the curve (with a
> > qdisk on the point and two parallel

Of course, I meant parallel to the axes...

> > 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)

Thanks Herbert. Where is this feature documented?

Maybe it could be useful to automate this by a command such as:

\psshowpoint{x^2/10}{3}

with optional PointSymbol=... (as in pst-eucl).
-- 
Denis