Think back to the grade school days when you needed a graphing calculator for class and you always filled it up full of games. Now things have changed so drastically that your music, video, and game playing iPhone can also be your graphing calculator.
PowerGraph provides you with all the functionality you would need out of a standard graphing calculator. It provides you two tabs, one for the calculator and one for the graph. This makes it very easy to switch back and forth between the two.
You're not losing any functionality with using this app over an actual graphing calculator. There are plenty of settings in the graph area for you to adjust to your liking. You can manually change all of the graphed and ungraphed functions, turn the axis, grid, and scale on or off. Plus you can change the background and foreground colors too.
While this app may be great for doing your homework, it's probably not something that's going to be allowed in a classroom. To teachers and professors, the iPhone is not an educational device. If you often need a graphing calculator and constantly find yourself without one, then keep this as a last page app.