Polynomial approximation to find function values

If we have the following data

Code:

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T = [296 301 306 309 320 333 341 349 353];

R = [143.1 116.3 98.5 88.9 62.5 43.7 35.1 29.2 27.2];

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T = Temperature (K)

R = Reistance (Ω)



and we know that

[tex]R=a \cdot e^{b/T}[/tex]

How can we, from these data, find the value of the constants a and b?



In the assignment it is suggested one draws a diagram that shows ln(R/Ω) as a function of 1/T and then use MATLAB "polyfit" function which gives a polynom approximation of this line and then use that polynom to find the values of a and b.



I have used the polyfit function in MATLAB to get a polynom approximation, but how does that polynom give me the constants a and b?