The linear optimization is explained on a practical industrial case. The Simplex Algorithm is presented. The Excel Solver is described.
I describe the Earth-centered (ECEF) cartesian and spherical coordinates as well as local ENU coordinates. I also derive transformations between them.
I derive the equation of the great circle on the spherical Earth, the formula for the shortest distance and other related formulas.
I derive equations of the torus and present an Octave program to draw it.
I present a simple zero-knowledge proof of map coloring with 3 colors.
My contributions to Math.Stackexchange.