Let f(x) = 4x. (a) Sketch the region R under the graph of f on the interval [0,2]. 8 y 2 2 y 8 9 2 y 00 8 6 + 2 PREVIOUS ANSWERS PRACTI 1 2 3 4 5 6 7 X X X 1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 2 3 4 5 6 7 Find its exact area using geometry. square units (b) Use a Riemann sum with four subintervals of equal length (n = 4) to approximate the area of R. Choose the representative points to be the left endpoints of the subintervals. square units (c) Repeat part (b) with eight subintervals of equal length (n = 8). square units (d) Compare the approximations obtained in parts (b) and (c) with the exact area found in part (a). Do the approximations improve with larger n? O Yes O No X