How to Derive Coefficients of the plynomial Eq. via interpolation calculations of hourly measured values of Net Power over Measured solar Data in Excel ?
Did you try to use the Excel command 'add trendline'? it fits the xy quantities to a specific polynomial based on you choice. The results also contain accuracy indicators such as the R^2.
Hello Haseeb Shah
Consider that the data [x1 x2 x3 x4 x5 x6 x7] are in columns A2:A8
and the data [y1 x2 y3 y4 y5 y6 y7] are in columns B2:B8
and we wish to fit the quartic polynomial y = a*x^4+ b*x^3 +c*x^2 +d*x + e
to the two data sets
The command to obtain the coefficients a, b, c, d, e is
= LINEST(B2:B8,A2:A8^{1,2,3, 4},TRUE,FALSE)
To determine coefficients of a a pentic polynomial we should write ^{1,2, 3, 4, 5} instead
I would recommend that you read two articles:
1.) The first is an article on curve fitting for measured hourly solar irradiation
https://www.irjet.net/archives/V2/i4/Irjet-v2i435.pdf
2.) Secondly as Amaechi J. Anyaegbunam suggested become more familiar with LINEST and Polynomial/Nonlinear curve fitting in Excel.
http://www.engineerexcel.com/nonlinear-curve-fitting-in-excel/
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