Fitting Curves

[ChristianDK]

Hi, I was hoping someone could help me perform some sort of regression for my data.

I want to come up with a fit for an unknown function. Available to me is data points (x,y) and the corresponding value of the first derivative of the same (x,y).

I only know how to interpolate the function using the data points (cspline,interp), but how do I include the given first derivatives?

Any comments or advice would be appreciated!
Christian