Upper and Lower Sums Applet
Input a function into f(x) to find the upper and lower sums approximations for the area under the curve. Use the slider for l to change the starting value and use the slider for u to change the ending value. The slider for n changes the number of rectangles shown in the upper and lower sums. To show the integral with the actual value for the area under the curve, click the checkbox "Show Integral."