Excel apparently uses Bezier curves to smooth its graphs. I *guess* it sets
up a lot of interpolation points for the purpose of charting any of its
trendlines.

If you are at all comfortable with using VBA, you might want to download my
cubic spline code (posted under Braden; watch out for the unintended line
breaks. See
http://groups-beta.google.com/group/...c412511748ebc9

An advanced search under the topic "cubic spline", author "Braden", group
"microsoft.public.excel.*" will yield more info.

HTH
Dave Braden

"lsu-i-like" wrote
in message ...

why is a polynomial trend line different from the original graph that
excel produces?


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