I'm not the developer, but as I was looking for some calculator/conversion apps (as I'm an engineering student in college) I stumbled upon... [app]Quick Graph[/app] Wish I would have had this in my calculus classes as it would have made the graphing homework problems a lot easier. Got it anyways to play around with it, and I'm very impressed. It can produce 3-d graphs and has a really easy input system. Oh, and it's free. Edit: Also, I've been a visitor to Touch Arcade for some time now, but this is first post. Sorry if I'm breaking any forum rules or duplicating some common knowledge.
If money is no object, I recommend SpaceTime. It seems there is nothing it can't do. It will cost you $25 which is more expensive than any of the competition but it is surprisingly powerful and cheaper than a real graphing calculator. Then again, it may be overkill for your needs. You can try out the Windows and mac versions of the software free for 30 days to get a feel for it. http://www.spacetime.us/ P.S. Welcome to TA.
Oh my, appreciate the heads up- seems like a mobile MATLAB. Now I just have to talk myself into spending the 30$ in my account for school purposes and not on loads of games.