numerical evaluation of T(R)

The ultimate purpose of the \(R\left(T\right)\) calibration is to be able to determine the temperature from a measurement of the thermometer resistance.  Rather than carry out a second Chebyshev fit for \(T\left(R\right)\) — which can lead to inconsistencies in the handling of the data — we instead find the value of \(T\) for which our calibration calculates a value of \(R\) corresponding to the measured \(R\) value by use of the Chebyshev.roots() root finding routine built into Chebyshev_fit
Suppose then that for \(x^{\ast}=x\left(T^{\ast}\right)\),  we find that \(R_{calc}\left(T^{\ast}\right)=\ R_{measured}\left(T_{measured}\right)\). Then