Simpson's Rule
Enter a function f(x) and an interval [a,b]. Move the slider to increase the number of intervals used - note the value of n is even. You can use the check-box to show the parabolas that are being used.
To change the viewing window, hold the shift button and left-click to drag the graph or use the scroll wheel to zoom in/out. You can also adjust the axes by holding the shift button and left-click on the axis you want to change.