merge polynomials

Below is the well known polynomial for a cubic spline.

xt=(((1-t)^3)*px1)+(((3*t)*(1-t)^2)*px2)+((3*t^2 * (1-t))*px3)+((t^3)*px4)

yt=(((1-t)^3)*py1)+(((3*t)*(1-t)^2)*py2)+((3*t^2 * (1-t))*py3)+((t^3)*py4)

As you see there are separate functions of x(t) and y(t) values of the curve.

I need a function that returns y(x).

I understand that this type of function will only work when the values of the x points are:

px1<px2<px3

or

px3<px2<px1

Engineering

Project ID: #391124

About the project