In this applet you can see an illustration of Simpson's rule. The integral [math] \int_a^b f(x)\, dx [/math] is approximated by dividing the interval into n pieces in which f(x) is approximated by quadratic polynomials. Change the value of n in order to make the approximation better. Change the value of i to se the i'th polynomial in the approximation. You may also change the function f.
Use shift+mouse to pan and zoom.