Question 19 (1 point) Listen Find the derivative. y = 4ex2 O A) 8xe B) 8xe 2x O C) 8xe 4x2 O D) 8xex2Question 20 (1 point) ) Listen Evaluate the integral. S dx 19-64 2 O A) sin 1 5x + C O B) tan-1 SX + C O C) + sin 1 5x + C O D) Itan 1 5x + CQuestion 21 (1 point) Listen Given the graph of f, find any values of x at which f ' is not defined. x O A) x = 2 O B) x = 2, 5 O C) x = 5 O D) Defined for all values of xQuestion 22 (1 point) Listen Find the limit, if it exists. x2 -4 lim x -2 x2 - 6x + 8 A ) - 2 O B) O O C) Does not exist O D) - 1Question 23 (1 point) () Listen Solve the problem. Round your answer, if appropriate. A man 6 ft tall walks at a rate of 3 ft/sec away from a lamppost that is 23 ft high. At what rate is the length of his shadow changing when he is 45 ft away from the lamppost? (Do not round your answer) O A)- 42 ft/sec O B) " ft/sec O c) 18 ft/sec O D) 18 17 ft/sec