find equation of data points and plot it

This task is just to get experience with simple data interpolation and extrapolation. In the table below you find two columns with energy data from a house in S¨odra Sandby. Construct the unique polynomial which interpolates the energy consumption. Plot the curves. Evaluate these polynomials to predict the energy consumption on Wednesday, April 15. Day Energy (kWh) 150407 27.93 150408 46.98 150409 31.95 150410 31.68 150411 21.00 Solve this task with three methods • by using Python or MATLAB’s commands polyfit and polyval, • by using Vandermonde’s approach • by using Lagrange polynomials.

how to plot the data points in x and y axis ? how to use polyfit and polyval in this case ?

[John D'Errico]

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