MARKS Page five 12. The diagram shows part of the graph of y = a cos bx. The shaded area is 1 2 unit2. What is the value of ∫ (acosbx)dx? 13. The function f (x) = 2x + 3 is defined on ,the set of real numbers. The graph with equation y = f (x) passes through the point P(1, b) and cuts the y-axis at Q as shown in the diagram. f (x) = 2x + 3 P(1, b) Q y x (a) What is the value of b? (b) (i) Copy the above diagram. On the same diagram, sketch the graph with equation y = f  –1(x). (ii) Write down the coordinates of the images of P and Q. (c) R (3,11) also lies on the graph with equation y = f (x). Find the coordinates of the image of R on the graph with equation y = 4 − f (x + 1). 2 1 1 3 2 y x π 4 3π 4 O O [Turn over 3π 4 0