[pstricks] tangential vector

[Herbert Voss]

Juergen Gilg schrieb:

>> this version pf pstricks-add.tex needs also the pst-fp.tex,
>> also available from http://voss.homedns.org/packages/pstricks-add
> \psPlotTangent without the _star-version_ generates a tangent line 
> symmetric to the given point, which is wonderful to show the slope of 
> the graph in whatever intervals.
> 
> What about a version that is not symmetric, and the user can enter the 
> x-Interval of the tangent line??? That would be extremely appreciated to 
> draw tangents without the detour of calculating the 1. derivative and 
> plot it as a \psplot if necessary to not have a symmetric tangent to a 
> given point of the graph.
> 
> The same could be done with the NORMAL.
> 
> Do you think that is possible?

sure, but there is always the problem with too many optional
arguments which make a macro more complicated.

Herbert