graphDS is a program for the Nintendo DS that can evaluate mathematical expressions and graph Cartesian, parametric, and polar equations.

Release notes:

In the latest version, I added a CAS, two new graphing modes (slope field and Euler’s method), and made calculation and graphing speeds 2.5x faster! Also be sure to check out all of graphDS’s useful built-in functions accessible via the catalog.

http://robertson.heliohost.org/