[list=1][*]Show the graph, the lower sum L, the upper sum U and the integral S in the interval [a;b] by selecting the marble [img]https://wiki.geogebra.org/uploads/thumb/3/34/Algebra_hidden.svg/16px-Algebra_hidden.svg.png[/img] next to them.[br][/*][*]Use the sliders in order to change the values of the interval [a;b] and the count of the rectangles for the lower and upper sum and explore how they are influencing the difference between the sums.[br][/*][/list]