18. [-/1 Points] DETAILS SCALC9 4.2.030. Use the form of the definition of the integral given in this theorem to evaluate the integral. 19. [-/1 Points] DETAILS SCALC9 4.2.033. Use the form of the definition of the integral given in this theorem to evaluate the integral. 10 ( x 3 - 2x 2 ) 8x20. [-/5 Points] DETAILS SCALC9 4.2.040. Consider the following- (x2 - 3x] dx (a) Find an approximation to the integral using a Riemann sum with right endpoints and n = 8. R B = (b) Draw a diagram to illustrate the approximation in part (a). 4 - 3- N -1 -1 -2 -2 -2 -2! O-3 DO-3! (c) Consider the following theorem. If / is integrable on [a, ]. then / "(x) ox = lim > xx) Ax. where Ax = 252 = 2 -2 and x, = a + /Ax. Use this to evaluate the integral. (d) Interpret the integral in part (c) as a difference of areas. The integral represents the area below the x-axis minus the area above the x-axis. The integral represents the area above the x-axis minus the area below the x-axis. Illustrate with a diagram. N 2 2 -1 -1 -2 DO-3 DO-3