[b]Type the following into Input Field[/b]:[br] [list][br][*] f(x) = <expression of your choice>[br][*] a = 0[br][*] b = 4[br][*] Area = Integral[f,a,b][br][/list][br][br]This will give you the actual area under the f(x) between a and b.[br][br][b]Type the following into the Input field:[/b][br] [list][br][*] n=10[br][*] UpperSum=UpperSum[f,a,b,n][br][*] LowerSum=LowerSum[f,a,b,n][br][*] Adjust the colors of Upper & LowerSum to be different[br][/list]