Here are some of my notes on some miscellaneous topics that came up during my research. Feel free to use them---attribution is appreciated but not required.
 Computing βN.
 Index-mapping for Spherical Harmonics Expansion.
 If you find Eq.(7) and Eq.(9) in  a bit mysterious, then the first three problems and solutions in this brief note may help you understand how these equations come about. These problems were assigned as homework problems in a freshman CS course I taught at CUA.