Notices

there is nice app called mathjinni and it has basic math functions and it can show you graph. but it would be nice to have simuliar applictation with 3D plot as well. if anyone is interesting it's possible to make basic functions as in simuliar programs for android or iphone.

I use gnuplot for 2D and 3D plots, both on my PC and on my phone. It is available in the repositories (but it may be in extras-devel in which case the usual warnings apply).

is it opt? and is it usable on phone? i still would prefer native app for maemo

i need an app to solve integrals, and differential eq, i tought the ti 85 emulator would but i can't even find the derivative of a function

any recommendation on that? :S

Yacas is a small computer algebra system that can do exactly that.

The N900 version can be found in extras-devel

However there are some (possible) drawbacks:
- not optified
- xterm based (textmode only), but that's fine
- you have to learn the syntax

For the last of these points, there is an interactive tutorial on the project homepage: yacas.sourceforge.net

@rikisky: well, if virtual link support for ATI85 ever gets implemented (you know, so we can transfer files to it - and no, I have no idea if this is even planned ), then there is a 3D graphing app for the TI-83+, the name of which escapes me, and an app called Symbolic that allows you to differentiate, integrate, etc.
@ZogG: I like native apps too, but for the mean time, you could try http://fooplot.com/, and see how well it runs on Maemo. I think it's pretty javascript-intensive, but the N900's browser is quite capable.

It would be great if someone could maintain and port Kayali to the N900. It uses PyQT and the interface is very simple; it uses maxima as backend and would probably look perfect when ported and adapted.

if you have internet access I recommend this for integrals

http://integrals.wolfram.com/index.jsp

Qalculate! might also be able to do integrals/differentials, I can't remember. In any case it's also in extras-devel (though iirc the screen layout needs some tweaking, patches welcome!)