Hi,

I did a search and found this error since Excel 95 but didn't see anything in recent searches.

I have a graph of points (XY scatter) and I have added a polynomial trendline. I then displayed the equation on the graph. I then used the equation in the spreadsheet to generate another column of "Y" values from X.

The trendline displayed on the graph looks great, but there is a very large error when comparing to the actual trendline equation values.

When I add another series to the graph of the trendline equation generated values they are nowhere close to the trendline displayed. The greater the polynomial the greater the error.

Microsoft acnowleged the issue years ago. Does anyone know if this function is still useless or if there is a fix. I am using Excel 2003.

I use a lot of trendlines in calculations. The logrithmic ones tend to be accurate if they fit your data.

Thanks for any help.

Regards,

Bob