Zim[0] (open source) has a lot of these features. It saves your notes as plain markdown files, but has a WYSIWYG editor. You can link between notes. Add pictures, formatting, etc.
There is also a huge number of extensions, back when I was doing math stuff I used the LaTeX one pretty often. Another useful one is the calculator extension, which can evaluate simple expressions like 3 * 5 =.
Since it's just plain markdown files, you can save to Dropbox, git, NFS, or anything else really. There's even a built-in plugin to automatically commit to git periodically (useful for standalone notebooks, since you don't really want to be opening git manually).
I've yet to find anything better, although I do wish it had better support for "anonymous" notes. That is, notes that I don't really feel like organizing or naming.
[0] http://www.zim-wiki.org/index.html
There is also a huge number of extensions, back when I was doing math stuff I used the LaTeX one pretty often. Another useful one is the calculator extension, which can evaluate simple expressions like 3 * 5 =.
Since it's just plain markdown files, you can save to Dropbox, git, NFS, or anything else really. There's even a built-in plugin to automatically commit to git periodically (useful for standalone notebooks, since you don't really want to be opening git manually).
I've yet to find anything better, although I do wish it had better support for "anonymous" notes. That is, notes that I don't really feel like organizing or naming.
[0] http://www.zim-wiki.org/index.html