display when touching a selected polynomial trendline
 

Hello,

I have a Chart Type xlXYScatterLinesNoMarkers with a 5th degree
polynomial trendline.
I know how to extract the parameters of that trendline with the
"Linest" formula, so I can build a formula that calculates the
derivatives of my trendline at any given point.

So calculating the value is not the problem.
What I want is that this derivative value pops up when I touch the
trendline at the given point.
I found out that touching a selected trendline with the cursor pops up
a little display saying something like "Series 1 Trendline1".
Something like that would be great.

Would this be too long a shot or is it feasible ? If not, I'd be
grateful for any other suggestion to display the derivative value by
just "tickling" the chart.

Thank you very very much.

Herman