I would like to get the 3rd order polynomial coefficients for an X-Y Chart
trendline into VB so I can automatically run a calculation at a extrapolated
X value and record this in my spreadsheet. If I can not get the coefficients
directly to do the calculation myself, can I plug in the X value and
calculate the resultant would help.

KMH wrote...
I would like to get the 3rd order polynomial coefficients for an X-Y
Chart trendline into VB so I can automatically run a calculation at a
extrapolated X value and record this in my spreadsheet. If I can not
get the coefficients directly to do the calculation myself, can I plug
in the X value and calculate the resultant would help.

See

http://groups.google.com/group/micro...440d271303e0d6

Googling splines might be helpful to you.

If you just want the coefficients, you can use LINEST. Select a range 4
cells wide and five cells high. Type this equation:

=LINEST(<yRange,<xRange^{1,2,3},TRUE,TRUE)

where xRange and yRange are the addresses of the X and Y values, and
array-enter the formula by holding CTRL+SHIFT while pressing ENTER. The
first row of cells show the 3rd, 2nd, 1st, and 0th order coefficients of the
poly fit. Check help for LINEST to learn what the rest of the LINEST output
includes.

- Jon
-------
Jon Peltier, Microsoft Excel MVP
Tutorials and Custom Solutions
Peltier Technical Services, Inc. - http://PeltierTech.com
_______


"Harlan Grove" wrote in message
oups.com...
KMH wrote...
I would like to get the 3rd order polynomial coefficients for an X-Y
Chart trendline into VB so I can automatically run a calculation at a
extrapolated X value and record this in my spreadsheet. If I can not
get the coefficients directly to do the calculation myself, can I plug
in the X value and calculate the resultant would help.

See

http://groups.google.com/group/micro...440d271303e0d6