Are there any C# math libraries that do interpolation / extrapolation [closed]

Question

For example, I have points

Y X
100 50
90 43
80 32

need to solve for y = 50

or

Y X
1/1/2009 100
1/3/2009 97
1/4/2009 94
1/5/2009 92
1/6/2009 91
1/7/2009 89

need to solve for y = 1/23/2009

Answer 1

The one I use is the numerics component of Math.NET http://numerics.mathdotnet.com/

It contains "various interpolation methods, including barycentric approaches and splines".

But as the saying goes, there are lies, damn lies and bicubic spline interpolations.