Part of me wants to just hand-write them and then maybe scan them, but that's not searchable/indexable, and doesn't lend itself well to version control.
Writing in TeX or LaTeX would make them searchable/indexable, but this seems a little heavyweight for just notes (like answers to exercises). I don't use TeX/LaTeX that often, so I feel like I'd be spending half of my mental energy figuring out how to format things, figuring out how to invoke the tools, what packages to install, etc.
Are there any nice solutions out there for this sort of thing?
It can search in handwritten notes, and can convert them to text (including converting handwritten math).
I don't do enough math writing or note taking to justify the cost of a Surface Pro, so don't personally know if it really works as well as it appears to in the video.
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)
Hopefully my research will converge with work duties at some point and I'll be writing a single alpha source for the very technical stuff.
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.
Later, I export the Quip doc to Markdown and make it searchable by adding it to Algolia.
I'll comment as someone who does hand-write and scan my notes. I date and number every page, then put a pile through a sheet-feeding scanner every so often. Sometimes I put date and page numbers in my code comments, so I can find my notes on where the code came from. I also enter a line of text (or more if necessary) about each scanned page so I can search that. Something I do in a brain-dead moment every month or two. It can be interesting to look back through the notes and see if I've forgotten about anything interesting.
Often I'll write out the math for something multiple times before I really understand it, and using a pen works much better for me. Only a small fraction of what I write out is worth TeXing up.
Use Pandoc; it basically abstracts all of the pain of LaTeX and allows you to write Markdown with equations. Writing macros is also useful to save typing cramps and clarify meaning -- a typical example is
\newcommand{\implies}{\Rightarrow}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.
I'm cataloguing math support in markdown tools at https://github.com/cben/mathdown/wiki/math-in-markdown (help welcome). If you don't know where to start, the first to check out are probably StackEdit, Atom + https://discuss.atom.io/t/using-atom-for-academic-writing/19....
I have a theory that a single pane styled in-place is nicer for quick writing than 2 source+preview pane. Typora, Texts.io, and my own https://mathdown.net do that.
If you do want full latex, try Overleaf.com, which has "rich text" mode where many constructs (sections, lists, math) are styled in-place (you could even hide the PDF pane).
(sample)
http://write-live.com/d/2aa4a21f-7bb0-4e02-929f-484dc8b7af10
(also check my other comment)
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
As many have said, an open-source app would be a godsend.
There really isn't much need for the multiplication symbol when we have side-by-side multiplication notation, and if x is a vector then you can underline it to distinguish it from the cross product (or just not name your vectors x). The "two c's" x has always looked bad to me and ends up getting confused with α and other things.
Drawings can be viewed / shared via web and are updated real-time (online whiteboard)
some samples:
http://write-live.com/d/dba21681-8d3f-4fbe-8b4b-e5c1983df934
http://docs.write-live.com/WriteliveServer/webview.html?d=2b...
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What I got was [ 11 ]
[ 01 ]I tried to write the equivalent of \widetilde{u} which it interpreted as u^n. On reflection, what I wrote did look like an n above the u. But if you work in the same field as me, you would immediately assume it was a widetilde.
Tried it out on a random equation from the Fourier transform wiki page:
Update -- it does work on an Android tablet, where hand gestures do count as drags. Very nice -- if only my tablet were twice as big so my fingers wouldn't get in each others' way.
Pretty slick. Now to get it as an open-source app.
Make sure you have touch events working in general. I don't think Firefox supports them yet on X11.
If I had to do it now I would use LaTeX though. For me, open always trumps proprietary when available, and because of their proprietary sort of walled garden nature, Adobe is not a company I would like to support.
Afterwards in the outside world, Office became the rule as I never needed to type mathematics again.
When we did a technical documentation project, DITA and Docbook were used instead, with WYSISWYG editors like oXygen.