Get the equation of the graph plotted into the workspace OR how the equation can be generated explicitly ?

I obtained the equation of a graph plotted using the Basic fitting option ( Plot the graph-> Tools-->Basic Fitting-->show equations). But, can some one explain how these equations are calculated( say, for a 3rd degree polynomial function)? Is there a code available for this? Any ideas is highly appreciated.

Answer 1

[jonas]

Let x and y be your data.

Use polyfit to fit coeffecients to your data using a third order polynomial.

P = polyfit(x, y, 3)

Evaluate the data at points xe

xe = ... 
ye = polyval(p, xe)

You can then plot xe and ye alongside your data.

If what you are really looking for is how the fitting is performed inside of polyfit, then read about least-square fitting