Convert hand drawn equations to LaTeX

It works quite well, but I wish there was a way to make small corrections (e.g. erase parts of my input).

The app keeps mistaking my handwritten "n" for "h", and my "k" for various obscure things like "|x:", and it's a bit of a pain to make small adjustments after most of the equation has been written: https://i.imgur.com/KneVGIU.png

Well, I use (Lua)LaTeX for exactly that kind of thing (for the notes I want to be searchable and archived in a repo; for other stuff just writing by hand on paper is usually the best solution, because I don't actually need that much notes to be stored as nifty .tex / .pdf files -- and for less math-heavy stuff, .md / pandoc toolchain is often enough).

To make LaTeX writing a bit less 'heavyweight', I maintain a .sty file for packages I use often + a template where I can just start writing + vim setup for editing the files + compile with latexmk.

When it comes to syntax and stuff like that, after writing my math B.Sc. thesis and who-knows-how-many homework reports with more or less same combo of packages and tools, I already know it and learning to use LaTeX no longer feels like an obstacle (..it's a cost I've already paid).

Whether a similar solution would be worth the effort for you depends on how much things LaTeX is good at you anticipate writing in the future. Academic papers, homework, stuff like that? Yes, it might be useful. Some random notes? Maybe not.

Don't kill me, but I actually took notes during math lectures using Word [1]. Since 2007 it has math support which you can either enter from the ribbon with lots of clicks (not recommended) or by typing something that for the most part resembles math in TeX, except that you use parentheses instead of curly braces and there are some smarts built-in that make typing much easier, simply because you're typing less, e.g. x^2y is equivalent to x^{2y} and a/b is equivalent to \frac{a}{b}.

Symbols are for the most part the same as in TeX, e.g. \alpha, etc.

The nicest thing of all that for interactive note-taking (at least for me) is that you see what you're entering. While you're typing you always get to see how it looks. This avoided (again, for me) many situations where I'd leave syntax errors in an equation just to get home and not remember where I'd forgot a closing brace.

The worst thing to enter via the plain-text format are large matrices, though that's no different from TeX, IMHO. In this case using the GUI facilities to enter them can actually be faster.

A (preliminary) description of the format they use can be found in Unicode Technical Note #28 [2], although that's not in all cases still the current implementation.

Fun thing is, there is even a Math Input Panel in Windows which does pretty much the same as that web app: Convert hand-written math into MathML. You can then insert it into various applications (Word works fine, Mathematica too, I think – I guess anything that can handle Presentation MathML on paste or drag/drop). [3]

[1] Sample: http://hypftier.de/files/uni/04/math/Vorlesungsmitschriften....

[2] http://unicode.org/notes/tn28/

[3] Excuse my horrible writing, but I have no pen on this machine: http://hypftier.de/temp/2016-01-13_080128.jpg – Clicking "Insert" while Word is focused, will then yield this: http://hypftier.de/temp/2016-01-13_080219.jpg (it even used the correct d (\dd) which has a small gap in the front and, depending on the font, can be upright)

Pandoc if you like markdown -- it allows LaTeX math and equations. Emacs org mode if you like emacs and not markdown.

Lately I've just found it easiest to use a text editor that has good keyboard support for entering unicode and just type everything in plain text. Vim's digraphs or Emacs's TeX input method are what I have in mind. It works fine for most personal notes (with a few unevaluated LaTeX macros on occasion) and it's not hard to go back later and convert it into a pandoc markdown document for nicer formatting.

LyX is a LaTeX editor which has a very good visual math entry panel.