Having a blog is addictive, isn't it?
After 1.75 years, the Math Identities Proofs page is still severely lacking. There are a few reasons for this. The first is that the format as it is now was only created about this time last year, and some effort was put into learning how to format it properly, even having to get creative with KaTex itself. The second has been due to limited time and emotional exhaustion from working too much and juggling that with being a voluntary caregiver, so the motivation pops in during short bursts and then dies for a while.
The third is a weird mental block in my mind that creating or finding the right image for scenarios that require them always feels difficult to start even though it is fairly easy, if that makes any sense. It's also the same mental hang-up for when I have to cover things I've never actually used before so that I can apply them to later sections, and even though those are also fairly easy.
The project started when I was keeping flash cards of identities to stay fresh on memory in college, and ending up with something like 350 of them, categorized. It didn't take me long to figure out that sometimes the internet and occasionally, to my surprise, somehow, even a textbook can give the wrong information. So I decided to learn the Insert - Equation feature on MS Word, added them all to a document, and started working on proofs here and there to show that they were in fact right. This was on and off for several years until about two years ago when I went over each category to make sure they were complete and everything was in order by how they could be proven, and I started making PDFs to share online. The only trouble is that nobody looks at PDFs anymore.
You wouldn't believe the number of proofs I've had to sift through on some of these, especially for derivatives where there's probably 4-5 for each one, and some vastly more complicated than others. I chose the simple and necessary routes and made them clearer. I've come across some that make me just angry because they use "proofs" in a higher category with assumptions in previous sections and circular logic, or they use circular logic for definitions that are assumed... wait... because they're just straight up incoherent.
This is all too common in hyperbolic trigonometry, where the analytic functions are the definitions, effectively leaving out a bunch of shit on how those are proven, and then using those to "prove" the other things with which you need to prove them. In fact, this is one of my renewed motivations, to get to that point in the page and spell it out, since I've had to figure out a final geometric proof in the process for it on my own. I've already set up the headers for it, which, unironically, mirrors the entire process for getting to the analytic circular trig functions. Curious how the circular analytic functions aren't considered definitions but the hyperbolic analytic functions are, by the way. I guess the use of imaginary units is too complicated to simply look at by trigonometry, even though they collapse into real numbers 100% of the time.
Anyways, I decided on the format of the existing page around this time last year and have worked on it when I can ever since, which has been a pretty great learning experience in itself. No one has ever provided any specific feedback, so there's no telling how many errors or how much confusion permeates the page. At least when I find it myself, the fixes are simple. And the good thing about it is that I am pressuring myself to make it right by putting myself on blast.
I want to finish. I want the links to expand the headers. Nobody wants this more than I do. It's like a baby I'm trying to teach how to walk so that it can grow up and function in the world. One person did offer to help with that and said it was easy, but I haven't heard from them since, which was early this year. So, I aim to make another focused attempt at it before officially moving onto derivatives, because it is bothersome and I can't let it go unfinished before everything else gets finished.
It feels weird getting compliments on the page at all because of that one element, but I'm grateful that people are looking at it and seeing its value.
Side note: I'm cranky as hell because my teeth have decided to torture me into insanity.