Under some conditions, Excel 2007 loses the leading coefficient with
polynomial fits. The development team know about this and a hotfix should
appear soon.
Use LINEST to get the values (see
http://people.stfx.ca/bliengme/ExcelTips/Polynomial.htm)
best wishes
--
Bernard V Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme
remove caps from email

"DanB" wrote in message
...
I am using an XY scatter plot. I have applied a polynominal trendline to
the
data. The trendline appears to be visually correct.

However, the displayed equation does not match the plotted trendline!
Sometimes it is obvious, the order isn't even correct. Other times the
coefficients are simply incorrect (which is worse). It is present on
several
charts, although they are within the same workbook.

There are numerous reports of this on the internet, but I do not see a
fix.
I do have SP1 installed. The document was created in Excel 2007, but as a
2003 workbook. The same issue is present on multiple computers with Excel
2007.

The equation however is correct in Excel 2003.

This strikes me as a major bug (assuming it isn't something I am doing
incorrectly) that is likely patched.

Thanks,
Dan