Please answer all questions and show work:

9) Find the interval of convergence of the series 1 . 3 . 5 . . . (2n -1) 7= 1 2 . 5 . 8 . . . (3n -1) 10) In n O The series converges. What does the with-term test say about the series ? O The series diverges. Vn O The ath-term test is inconclusive. O None of the above 11) Given x = 21 + 3, and y = f- - 1, find dy/dx. O 3 O 3 O 2 2 12) For an unknown vector a and the given vector b = (3, 4, 0) , it is also given that a x b = (24, - 18, c) , where c is unknown. Find the value of c