The success of the fit ultimately depends on proper choice of P, Q, and initial values for \(\kappa_{i,p}\) and \(\)\(\gamma_{i,q}\).  Guidance on how to choose these values is provided in section \ref{638204} : R(B,T) calibration.

Thermometer Sensitivity

Since the first derivative of a Chebyshev polynomial is also a Chebyshev polynomial \cite{Karageorghis_1988,Fortune_2000,Barrio_2004}, both \(R\) and the dimensionless sensitivity \(\eta\)  can be directly calculated from \(T\) once the values of   \(c_i\) have been determined. Specifically,