Hi, this is more of a review question and I'm just looking at solutions of natural cubic spline equations and some will give the cubic spline as:
1. s(x) = a + bx + cx^2 + dx^3
while other pages will give:
2. s(x) = a + b(x - t) + c(x-t)^2 + d(x-t)^3
where t is the first coordinate in the each point given. I'm not sure which is the standard version and it can make a difference when I evaluate the derivatives so any clarification is appreciated.