Alternately, David Braden has posted VBA code to extract the
coefficients (rounded per display - therefore format the chart equation
as Scientific with 14 decimal places) directly from the chart into cells

http://groups.google.com/groups?selm....microsoft.com

The choice would depend on what version of Excel you are running. In
versions prior to 2003, LINEST/LOGEST/TREND/GROWTH used numerically
inferior algorithms that could give wrong answers in numerically
challenging situations, while the chart trendline algorithms have always
been excellent.

If you have 2003, download the most recent hotfixes and be suspicious if
any coefficients are estimated to be exactly zero.

Jerry

Andy Pope wrote:

Hi Phil,

Have a look at Bernard Liengme's examples of using worksheet formula to
determine equation elements.
http://www.stfx.ca/people/bliengme/ExcelTips

Cheers
Andy

Phil Hageman wrote:

When adding a trendline on a chart, one option is to add the trendline
equation to the chart. Is there a way to also populate off-chart
cells with the various factors of the equation?

For example: the equation on a chart is: y = 5.1460E+05Ln(x) -
2.5051E+06. The 5.1460E+05Ln(x) value would be found in cell A1, and
the €“2.5051E+06 value in cell A2. As values are added to the data
matrix and the equation changes, the cell values would change
accordingly.