Online tools for doing symbolic mathematics 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)

 A: There is QuickMath which works in it limited range if you can avoid the advertising.
A: There's a magma calculator online here, but your programs are limited to 60 seconds which should be sufficient for most things.
A: This one is good too:
https://www.mathway.com/problemwidget.aspx
(blah blah, 30 char limit, blah blah)
A: Added: I found the Wikipedia article Comparison of Computer Algebra Systems from a link on Sage's site. Various systems are listed in tables, each identifying cost, features, etc. for each of the programs.  That may help you ultimately determine what works best for YOU!End "Added"

I can't speak for hicalc (I've not heard of it!) but IMO, a good choice would be Sage Notebook: it integrates a whole bunch programs: GAP, R (statistics), Pari, etc. (see more programs listed below), and you can program, as well (Python?).  I'm not sure about its graphing capabilities; though it does seem to come equipped with some graphing functionality. You can create your own account if you scroll down to the bottom of the webpage linked immediately above. (You can also peruse sample "Worksheets" from "notebooks").
Another "plus" about Sage Notebook is that you can create folders, save your work, etc, on-line, and can then thus access it (when on-line again) and pick up where you left off at another time.
Mathematics packages contained in Sage
Algebra: GAP, Maxima, Singular
Algebraic Geometry: Singular
Arbitrary Precision Arithmetic: MPIR, MPFR, MPFI, NTL, mpmath
Arithmetic Geometry: PARI/GP, NTL, mwrank, ecm 
Calculus:   Maxima, SymPy, GiNaC 
Combinatorics:  Symmetrica, Sage-Combinat 
Linear Algebra: ATLAS, BLAS, LAPACK, NumPy, LinBox, IML, GSL 
Graph Theory:   NetworkX 
Group Theory:   GAP 
Numerical computation:  GSL, SciPy, NumPy, ATLAS 
Number Theory:  PARI/GP, FLINT, NTL 
Other packages contained in Sage 
Command line:   IPython
Database:   ZODB, Python Pickles, SQLite
Graphical Interface:    Sage Notebook, jsmath
Graphics:   Matplotlib, Tachyon3d, GD, Jmol
Interactive programming language:   Python
Networking:     Twisted
More details available here Wikipedia on Sage.
See also Sage Documentation, where you can find tutorials, manuals, references, etc. available on-line and as downloads (e.g. pdf)...I've personally found the "help" mechanism in Sage quite valuable.
A: If you are looking for symbolic calculations using Octave / Matlab,
 SCaVis is a good choice. You can learn build-in jMatLab program.
There is also a tutorial on jLearn page.
A: 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
A: Mathics is “a free, light-weight alternative to Mathematica” built using Python and SymPy. It has an online version:
  
A: Checkout http://live.sympy.org/, which is a SymPy session that runs on the Google App engine. It uses a persistent session system, so you can do more than just one-liners. It's actually just a Python shell, so you can do all kinds of nontrivial stuff. The only limitation is that the Google App Engine has a time limit on calculations (I think it's like 30 seconds or something).  
You can also get nice LaTeX output by choosing "LaTeX" from the popup (the default is ASCII, which is more compatible, but still looks nice).
A: There are various online code compilers you could use for this purpose, assuming you know an appropriate language. Both the linked services support Haskell, a particular favorite of mine.
A: You may try this online Computer Algebra Calculator:
http://www.omega-math.com
It only requires free registraton. There is also a quick reference at
http://www.omega-math.com/nhome/qr.jsp
