special-sample-challenge

I have updated the Maxima source for the special sample, made a screenshot, and wrote a draft for a challenge/task in notepad. Perhaps I will post it to the forum. This is certainly not the biggest or most urgent problem to solve, but perhaps also not the smallest or least interesting.

Maxima source code is available.

Here is the text for the challenge/task:

In my other blog post I described a case (screenshot 7) where a function z = f(x, y) has a minimum which just touches the plane z = 0. I made a cross section through the 3D surface, giving a function z = f(x), the equation of which is available in uploaded text files.

The function depends on a parameter L - the original length of the springs in the physical (federgraph) model, all other parameters are kept constant in the special sample.

Question: What exact value of L does correspond with the situation in screenshot 7 where the minimum touches the floor?

Not only do I want to know what the value of L is, I also would like to see how you approach the problem, what tricks you apply, and which software you use.

The Maxima source code is at pastebin.