Please provide explanations for the problems underlined in blue

EXERCISES 3.6 Derivative Calculations 25. y = x2 sin4 x + xcos 2x 26. y = * sin x - cos3x In Exercises 1-8, given y = f(u) and u = g(x), find dy/ dx = dy/ dx = f' (8(x))8'(x). 1. y = 6u - 9, u = (1/2)x4 2. y = 213, u = 8x - 1 27. y = 10(3x - 2)6 + ( 4 -: 1 3. y = sinu, u = 3x + 1 4. y = cos u, u = 28. y = (5 - 2x) 3+ 8x+1 5. y = Vu, u = sin x 29. y = (4x + 3)4(x + 1)-3 30. y = (2x - 5)-1(x2 - 5x) 6 6. y = sinu, u = x - cos x Z y = tan u, u = 1.x2 8. y = -secu, u= + 7x 31. h(x) = x tan (2V/x) + 7 32. k(x) = x2 sec x In Exercises 9-18, write the function in the form y = f(u) and tan 3x u = g(x). Then find dy / dx as a function of x. 33. f(x) = V7 + x sec x 34. 8(x) = (x + 7 ) 4 9. y = (2x + 1)5 10. y = (4 - 3x) 2 1 + sin 3t 11. y = 1 - Vx ) - 10 35. f(0) = sin 0 36. 8(1) = 12. y = 1 + cos 0 3 - 2t 2 37. r = sin (02) cos (20) 38. r = sec V0tan 13. y = 8 + x 14. y = V3x2 - 4x + 6 39. q = sin 40. q = cot sin t 15. y = sec (tan x) 16. y = cot T - x 17. y = tan x 18. y = 5cos 4x In Exercises 41-58, find dy / dt. Find the derivatives of the functions in Exercises 19-40. 41. y = sin? (Tit - 2) 42. y = sec2 it 19. p = V3 - t 43. y = (1 + cos 2t)-4 44. y = (1 + cot (t/2))-2 20. q = V2r -12 45. y = (t tan t) 10 46. y = (13/4 sin t) 4/3 21. S = 4 3 TT -sin 3t + 57 #-cos 5t 22. s = sin 3 7rt + COS 3 Tit 2 2 12 3 3t - 4-5 47. y = 6 (sec 0 - tan 0)3/2 - 4t 48. y = 23. r = (csc 0 + cot A)-1 5t + 2