The following function is positive and negative on the given interval. f(x) = sin 3x; 2 12 50 a. Sketch the function on the given interval. b. Approximate the net area bounded by the graph of f and the x-axis on the interval using a left, right, and midpoint Riemann sum with n = 4. C. Use the sketch in part (a) to show which intervals of 7,2x make positive and negative contributions to the net area. a. Choose the correct answer below. O A. O B. O C. OD. Ay Ay 2- 2- 2- 1- X X X 0- O- -1- -2- b. Use a calculator to approximate the area. The net area, approximated using the left Riemann sum with n = 4, is (Do not round until the final answer. Then round to three decimal places as needed.)