TITLE: Online tools for doing symbolic mathematics
QUESTION [31 upvotes]: This question is similar to this one, but specifically relates to resources available strictly as on-line web apps.  Examples include:

Wolfram Alpha
Sage Notebook
hicalc

not sure what this is; the site is currently blocked from my location.  I got it from the first link above.


Some basic needs:

Ability to do symbolic manipulation on par with what you'd use Mathematica for
Should be possible to do more than 'one-liners' (unlike Wolfram Alpha)

REPLY [2 votes]: As this question is old, (today 11/29/2106), a lot of the links in the answers are now broken. Here is an up to date list.

Symbolab
Wolfram Alpha
SymPy Live
Cymath