Cumulative area


The plot on the left is the graph of f. Dragging the red dot along the x-axis displays the cumulative area under the graph. At the same time, the plot on the right displays the graph of the cumulative area, that is, the graph of F, where x is the current position of the red dot. In other words, the height of the blue line on the right is equal to the area of the blue region on the left.