How to extract the function from curve fitting tool in Matlab

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zein
zein 2020-12-17
评论： zein 2021-1-8
I want to extract the function for my data points. I used interpolant witg linear method as indicated in the figure below.
Is it possible to extract a function for the new curve produced by curve fitting as i want to integrate the equation to get the area under the curve?

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采纳的回答

Steven Lord
Steven Lord 2020-12-22
You can call integrate on the cfit object. See the documentation page for more information.

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Ameer Hamza
Ameer Hamza 2020-12-17
编辑：Ameer Hamza 2020-12-17
No, in the case of interpolated curve fitting, it is not possible to get a nice and simple equation. It uses several linear equations in a piecewise manner to create the curve. However, it is still possible to integrate it. First, export the model to the workspace by right-clicking it in the "Table of Fits" section. The export model (name it fittedmodel in this example) supports functional syntax to evaluate the value. For example, you can write
fittedmodel(0.01)
to get the value at x = 0.01. You can integrate it like this
integral(@(x) fittedmodel(x).', 0, 0.03)
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zein
zein 2021-1-8
Is it possible to differentiate the save function for different values of x?

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