12. The radius of convergence of $ 3x" is 1=0 a. 3 b. c. 1 d. Do e. None of the above 43. The radius of convergence of _ (3x)" is a. 3 b. c. 1 d. Do e. None of the above 44. The interval of convergence of E (-1)" " is a. [-3,3] b. (-1, 1] c. (-3, 3] d. [-1, 1] e. None of the above 45. The interval of convergence of is a. (-1, 1 ) b. (-1, 1] c. [-1, 1) d. [-1, 1] e. None of the above 46. The radius of convergence of E n is a. b. c. 0 d. Do e. None of the above 47. The interval of convergence of ) = is a. (-1. 1 b. (-4, 4] c. (-4, 4) d. R e. None of the above 48. The radius of convergence of a. 4 b. c. 2 d. Do e. None of the above