b-spline nurbs derivetives 6th order

I can do this. Can I ask is this for homework at college or for some other purpose? I would write a program to calculate the polynomial coefficients of the basis functions for each segment between knots of the nurbs curve, then to compute a point on the curve given its control points, their weights, and the parameter value (the position from 0 to 1, start to end, on the curve). A nurbs curve is parametric, like i->(x,y) for i in [0,1], they do not normally factor well into an x->y sort of function/relation. But I can write numerical code to find the y values for an x value if you really need that. This would be comparatively slow. Why do you need to have an x->y function? As it is a serious application rather than homework, I have decided to increase my bid to $100, I hope that is acceptable.