This app gives you the area under a curve.[br]It shows you the Upper Sum, Lower Sum, Difference, [br]and Integral. You can change the number of intervals[br]the space is broken into by using the slider. Watch how [br]the values change, and make predictions about how the [br]values are related.

Illustrating the concept of partial derivatives using the function [math]f(x,y) = sin(x) + cos(y)[/math].[br]Drag point A (the [color=#00FF00]GREEN[/color] point)