See my website for the use of LINEST to get coefficients of polynomial fit
into cells
Then you are using Excel's maximum precision.

--
Bernard Liengme
www.stfx.ca/people/bliengme
remove CAPS in email address


"Eugepticus" wrote in message
om...
Disregard the previous message. The problem is due to the rounding off.
The
trendline calculation is OK.
Gene