1. Calculate the following derivatives. Use the log identities to simplify before taking derivatives. 15. y = In 7x 16. y = x2 In x 17. y = In x2 18. y = In 2x8 1 + In x3 19. y = In | sin x| 20. y = 4x3 21. y = In (x4 + 1) 22. y = In Vx4+ x2 x+1 23. y = In 24. y = x Inx - x x - 1