Depends on the model underlying your trendline. See Help for:
FORECAST() - if the model is a straight line
TREND() - for a general linear model (including polynomials)
GROWTH() - for general log-linear models
Alternately, you can get the coefficients of the equation and produce
your own forecasts. See Help for:
SLOPE() & INTERCEPT() - if the model is a straight line
LINEST() - for a general linear model (including polynomials)
LOGEST() - for general log-linear models
Alternately, you can use David Braden's code
http://groups.google.com/[email protected]
to read coefficients from the chart trendline equation, which may be
better numerically in Excel versions prior to 2003.
Jerry
