XlXtrFun Extra Functions
(5/2)
Description
XlXtrFun™ Extra Functions for Microsoft Excel
Three Dimensional Interpolate and Extrapolate Functions; Two Dimensional Interpolate, Extrapolate, Cubic Spline, Polynomial Curve Fitting, Line Intersections, Minima, Maxima, First Derivative, Second Derivative, and other functions.Free download.
XlXtrFun.xll is a collection of functions which extends the capabilities of Microsoft Excel; developed primarily to facilitate, interpolation of 2-dimensional and 3-dimensional data, and simplify 2-variable curve fitting. XlXtrFun has been used for years by engineering and research and development personnel on every continent who need to interpolate, extrapolate, and curve fit data rapidly, reliably, and with a virtually non-existent learning curve.
If you work with real-life data and want to interpolate, extrapolate, or curve fit, then you will find these functions very useful.
Calculation Reference
http://www.xlxtrfun.com/XlXtrFun/XlXtrFun.htm
Calculation Preview
(5/2)
Full download access to any calculation is available to users with a paid or awarded subscription (XLC Pro).
Subscriptions are free to contributors to the site, alternatively they can be purchased.
Click here for information on subscriptions.
The trendline method described in the article is a better approach as it only uses Excel native functions. I hope this is a good solution for you.