◄Back

# Long description

The figure is in two parts: (a) and (b). Each part shows a set of Cartesian axes labelled x and y and focuses on the upper-right quadrant. Both parts have the same curve labelled y equals f of x which is a curve going through the origin from the lower-left quadrant but concentrated mainly in the upper-right quadrant and it has two local maximum points and one local minimum. In both parts the points a and b are marked on the positive x-axis with a being nearer the origin. A bold line joins the points a and b. There are five irregular subintervals shown as rectangles and shaded. Part (a) has the top of each shaded rectangle touching the graph from below. Part (b) has the top of each shaded rectangle touching the graph from above.