PocketCAS is a free interface to the open-source Computer Algebra System giac/xcas.

xcas enables you to quickly solve complex algebraic problems, e.g. symbolic and numeric integration and derivation of non-trivial functions, solving differential equations etc. It has also a huge support for problems of linear algebra, like solving linear equation systems, multiplying and inverting matrices, finding eigenvalues (and eigenvectors, of course) and much more. If you do statistics or number theory, you will like xcas’ great functionality in those areas, too!

Changes:

Changed integration function from int(…) to integrate(…) in keyboard.xml. This shows an integration symbol in TeX output.
Added images for the following functions: sqrt, approx, backspace, newline

http://forum.xda-developers.com/showthread.php?t=415169