Jon:

Yes, that method occured to me too... so thanks for the two pointers which
might make life much easier. For right now I think the copy-paste method is
going to suffice, but in future...

Graham

--
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Graham Wideman
Microsoft Visio MVP
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Book/Tools:
Visio 2003 Developer's Survival Pack
Resources for programmable diagramming at:
http://www.diagramantics.com
"Jon Peltier" wrote in message
...
Graham -

You could access the trendline formula using the LINEST worksheet formula.
Bernard Liengme shows how to do this for a polynomial fit, which should
help you figure it out for another fitted model:

http://www.stfx.ca/people/bliengme/E...Polynomial.htm

Or you could extract it directly from the trendline formula using Dave
Braden's parsing macro:

http://www.google.co.uk/groups?selm=....microsoft.com

Now put some X values in a column at the frequency you want, and use the
coefficients you've determined to calculate the corresponding Y values in
the next column, and put your own custom trendline on the chart.

- Jon
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Jon Peltier, Microsoft Excel MVP
Peltier Technical Services
Tutorials and Custom Solutions
http://PeltierTech.com/
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