Excel can handle polynomial trendlines up to 6th order through the Add
Trendline command. I would like to be able to add a trendline up to the 8th
order. Google searches showed me how to compute this, but I am wondering if
there is an easier way. I tried using VBA :

ActiveChart.SeriesCollection(1).Select
ActiveChart.SeriesCollection(1).Trendlines.Add(Typ e:=xlPolynomial,
Order:=6 _
, Forward:=0, Backward:=0, DisplayEquation:=False, DisplayRSquared:=
_
False).Select

and then changing the Order:=8 but it would not work.

Any great ideas?

Thanks,

Frank