As suggested by the title, I'm attempting to fit a piecewise-defined curve to a set of data points. This is also the first time I have used Mathcad, so it is exceedingly likely I'm missing something obvious. My worksheet is attached to this post.
I'm attempting to follow the example at http://www.phys.uconn.edu/~hamilton/phys258/P/genfit.pdf, but when I call the genfit routine, I get the error "This value must be a function".
So, question number 1: what is this error message trying to tell me, and how can I resolve it?
While I have your attention, I also have question number 2. The function is a horrible mess because I'm trying to combine data points with continuity restrictions. I don't know how to specify symbolic relations between fitting parameters (e.g. forcing the second derivative to be continuous at x = 60 yields "e = b + 24"). So I've solved the continuity restrictions by hand and substituted them back in. Is there a way to get Mathcad to recognize additional restrictions on the fitting parameters beyond just the list of data points?
And branching further afield still, question number 3: can Mathcad do symbolic differentiation of piecewise functions? When I ask for d/dx(f), I get an error message that f "must be a scalar".
Thanks in advance for any help you all can offer.
