I looked in the NASA archives for the work of Katherine Johnson described so dramatically in the film “Hidden Figures”. I found this 1960 paper:
In particular, I was struck by the film’s use of “Euler’s Method” as the critical plot point, and sadly couldn’t find anything about the use of that method in the archive, nor mention of it in the text of Margot Lee Shetterly’s book on which the film “Hidden Figures” is based.
I did however read in the paper about a “iterative procedure” needed to solve for one variable.
Turns out the sequence of equations described in the report, when assembled into an expression in the single variable of interest, defines a contraction mapping and so converges by functional iteration, as is numerically demonstrated in the paper.
At the bottom I’ve linked a fuller treatment in a .wxmx file. Briefly, the authors describe the problem:
Here’s everything from the paper needed to do that in Maxima:
I put together equations 19,20,8, and 9, together with all those constants defined by the paper and customized trig function that act on angles measured in degrees, into an expression of the form
and applied the built-in Maxima numerical solver find_root(). The result agrees reasonably well with the result quoted in the paper.
In the above, I computed the derivative of the mapping evaluated at the solution and found that the value is much less than one, showing it is a contraction.