*3. The following function is positive and negative on the given interval. f(x) = 9- x2; [0,4] 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 [0,4] make positive and negative contributions to the net area. a. Choose the correct answer below. O A. OB. Oc. D. Ay 18+ Ay 18+ AY 48- 12- Ay 18 12- 12- 12- 6- 6- 6- 0- 0+ 0- -6- -6- -6 -12- 42 48- -12- -12 -18 -18- -18- b. The net area, approximated using the left Riemann sum, is The net area, approximated using the right Riemann sum, is The net area, approximated using the midpoint Riemann sum, is c. Which intervals of [0,4] make positive and negative contributions to the net area? Choose the correct answer below. O A. Positive contributions on [2,4); negative contributions on [0,2] O B. Positive contributions on [0,3]; negative contributions on [3,4] O C. Positive contributions on [3,4]; negative contributions on [0,3] O D. Positive contributions on [0,2]; negative contributions on [2,4]