____Subject:____
The objective of this Add-on is to create a tool that contain functions to interpolate and extrapolate from a data contained in a spreadsheet. 
All functions are developed to behave in the same way that the interpolation Add-in created by Jose Ivan Martinez Garcia for Excel.
It will make possible a kind of interoperability among LibreOffice Calc, Google Sheet in interpolation matter.

____How to use:____
This Add-on does not have special UI on the sidebar. You have to use it as native function of Google Sheet
1.	Select a cell.
2.	Type the function related to the interpolation that you wish to solve. [Example: "interpo"]
3.	Select or type the argument as requested by the function [Example: F6,C5:C11, etc.]
4.	Review that function and argument are properly selected and press enter [Example: "interpo(F6,C5:C11,D5:D11)" ].

____Packaged Functions included in this Add-on until now:____
interpo(x, XRange, YRange)          Linear interpolation with one parameter and two source ranges
interpo2(x, y, Range)               Linear interpolation with two parameters and a table source
cercha(x, Range, keyArg, v1, v2)    Spline interpolation with one parameter and a table source range
cerchapi(Range, keyArg, v1, v2)     Determine the initial slope (1st derivative) at the first point of first spline - Matlab ® (function csape)
cerchapf(Range, keyArg, v1, v2)     Determine the final slope at the last point of the last spline
cerchaci(Range, keyArg, v1, v2)     Determine the initial curvature (2nd derivative) at the first point of the first spline
cerchacf(Range, keyArg, v1, v2)     Determine the final curvature (2nd derivative) at the last point of the last spline
cerchara(Range, keyArg, v1, v2)     Determine the curvature radius of the segments in the given points
cercharaxy(Range, keyArg, v1, v2)   Determine the centers of curvature coordinates of the segment, in the given points
cerchap(Range, keyArg, v1, v2)      Determine the slopes (1st derivative) at the given (well-known) points.
cerchac(Range, keyArg, v1, v2)      Determine the polynomial (spline) coefficient
cerchacoef(Range, keyArg, v1, v2)   Determine the polynomial (spline) coefficient respected to the origin of coordinates
cercharea(Range, keyArg, v1, v2, w1, w2)    Determine the area under splines until the Xs axis.
cerchamx(Range, keyArg, v1, v2, w1, w2)     Determine the static moment under splines area respect the Xs axis.
cerchamy(Range, keyArg, v1, v2, w1, w2)     Determine the static moment under splines area respect the Ys axis.
cercham2x(Range, keyArg, v1, v2, w1, w2)    Determine the second static inertial moment under splines area respect the Xs axis.
cercham2y(Range, keyArg, v1, v2, w1, w2)    Determine the second static inertial moment under splines area respect the Ys axis.
cerchap2(Range, keyArg, v1, v2, w1, w2)     Determine the inertial product under the spline with respect to the Xs and Ys axes.
cerchaxg(Range, keyArg, v1, v2, w1, w2)     Determine the longitudinal coordinate of the gravity center of the area formed under the spline.
cerchayg(Range, keyArg, v1, v2, w1, w2)     Determine the vertical coordinate of the gravity center of the area formed under the spline.

____Finally:____
-	This Add-on is a spare time project. Just to share it and have fun. Nevertheless, I'll be glad receiving donations at:
https://www.paypal.com/donate?hosted_button_id=FDNRQV526629Q
-	Others functions will be added in further releases. If you wish a special function related to interpolation, do not hesitate to requesting it to me at manuel.astros1980@gmail.com. I will revise it and put it in a list.
-	Detailed Help for this Interpolation Add-on can be found published in: https://sites.google.com/view/interpolation/documentation
-	I want to special thanks to by Jose Ivan Martinez Garcia who originally create the Add-in for Excel.
Don’t forget to rate me

____About Developer:____
Manuel V. Astros Montezuma.
Mechanical Engineer with more than 18-year experience as a project engineer and piping material engineer
Email:  (manuel.astros1980@gmail.com)
Linked in: www.linkedin.com/in/manuel-vladimir-astros-montezuma