Having been completely perplexed by VBAHack's comprehensive tutorial regarding fitting cubic spline curves to data points, I have a question that perhaps VBAHack would be able to answer.
I have 4 data coordinates and I wish to (programatically) interpolate a curve between the middle two of them (see screenshot attached)...
(1, 1.5), (2, 0.5), (3, 2.5), (4, 3.5)
I am not familiar with advanced mathematics or matrices though (which is where I had trouble with the tutorial, I'm certainly no mathematician ), believe me I did try quite hard to understand VBAHack's tutorial but I soon got lost in the mathematical complexity.
I'd be much obliged if someone could walk me through how to convert those 4 coordinates into a polynomial expression of the sort that I can just plug x values into and get y values out of it.
I don't want code, I can work that part out if I could come to understand the method to obtain the polynomial from the 4 coordinates, which I guess would be something like: y=ax4 + bx3 + cx2 + dx + e
The curve I end up with doesn't have to be particularly accurate, as long as it looks about right.
), believe me I did try quite hard to understand VBAHack's tutorial but I soon got lost in the mathematical complexity.
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