3-20 Use the Ratio Test to determine whether the series is convergent or divergent. 1 8 3. _ n (-2) " 5 7 4. n- 5. 2 (-1)"-1 37 Co (-3 ) " 2 " n 3 6. > (2n + 1)! 1 00 K! 8. > ke k 10" 9. n! no] (n + 1)42n+1 10. no1 100" 11. > n 10 (-3) " -1 12. > (-10) "+1 13. > Cos (n TT / 3) 14. > n! now ] n! 100 100" 15. > (2n)! n! 16. > ( n ! ) 2 2! 3! 17. 1 - 4! + 1 . 3 1 . 3 . 5 1 . 3 . 5 . 7 + ... n! + (- 1) "-1 + ... 1 . 3 . 5 . ... . (2n - 1) 2 2.5 2.5.8 2 . 5 . 8 . 11 18. + + + ... 3 3.5 3 . 5 . 7 3 . 5. 7 . 9 2 . 4 . 6 . ... . (2n) 19. n! 2"n! 20. 2 (-1)" 5 . 8 . 11 . ... . (3n + 2)