560 CHAPTER 5 Trigonometric Functions Write each function in terms of its cofunction. See Example 2. 23. cos 30° 24. sin45° 25. csc 60° 26. cot 73° 27. sec39° 28. tan25.4° 29. sin38.7° 30. csc 49.9° Give the exact value of each expression. See Example 3. 31. tan30° 32. cot 30° 33. sin30° 34. cos 30° 35. sec30° 36. csc30° 37. csc45° 38. sec45° 39. cos 45° 40. cot 45° 41. tan45° 42. sin45° 43. sin60° 44. cos 60° 45. tan60° 46. csc60° Find a formula for the area of each figure in terms of s. 55. 45° 45° s s 56. s 60° 60° 60° s s Concept Check Work each problem. 47. Find the equation of the line that passes through the origin and makes a 30° angle with the x-axis. 48. Find the equation of the line that passes through the origin and makes a 60° angle with the x-axis. 49. What angle does the line y = 23x make with the positive x-axis? 50. What angle does the line y = 23 3 x make with the positive x-axis? Find the exact value of the variables in each figure. 51. z y w 9 30° 60° x 52. 45° 24 d c b a 60° 53. 15 90° 45° 45° 30° r t q p 54. 7 q n m a 60° 45° Concept Check Match each angle in Column I with its reference angle in Column II. Choices may be used once, more than once, or not at all. See Example 4. I 57. 98° 58. 212° 59. -135° 60. -60° 61. 750° 62. 480° II A. 45° B. 60° C. 82° D. 30° E. 38° F. 32°
RkJQdWJsaXNoZXIy NjM5ODQ=