Enter your function and interval. Use the n slider to select the number of subintervals and the L-M-R slider to choose your sample points as left, right, or midpoints. Note that this illustrates the limit definition of the definite integral. [br][br]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.