Finding optimal coefficients while fitting multiple data in matlab

There are 3 sets of data and I need to use exponential fitting. How to get a set of coefficients to satisfy the best fit to the three sets of data?

Answer 1

[Matt J]

If they all follow the same model, just concatenate the 3 data sets and fit them as a single set.

If each data set has a different set of parameters. Just perform 3 separate fits.

[Yang Metin]

They have the same x coordinate.

[Matt J]

Not relevant. Just make 3 copies of the x-coordinate vector and join them together.