I am searching for a way to fit polynomials to experimental data of heat capacity and temperature.
Easily done for a TF1 or a TGraph (files attached).
The polynomial coefficients are meant for use in some other software.
The tricky point: One predefined value has to be matched exactly.
I have to use several complementary polynomials for different temperature regions. For the software to be stable, I have to define some points where the polynomials intersect, having identical values.
The intersection points have to be at specific temperatures.
What is the best way to set one pair of values which the polynomial does match perfectly?