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Pre-Calc Trig ~1~ NJCTL.org
Unit Circle – Class Work
Find the exact value of the given expression.
1. 𝑐𝑜𝑠4𝜋
3 2. 𝑠𝑖𝑛
7𝜋
4 3. 𝑠𝑒𝑐
2𝜋
3
4. 𝑡𝑎𝑛−5𝜋
6 5. 𝑐𝑜𝑡
15𝜋
4 6. 𝑐𝑠𝑐
−9𝜋
2
7. Given the terminal point (3
7,
−2√10
7) find tanθ
8. Given the terminal point (−5
13,
−12
13) find cotθ
9. Knowing cosx=2
3 and the terminal point is in the fourth quadrant find sinx.
10. Knowing cotx=4
5 and the terminal point is in the third quadrant find secx.
−𝟏
𝟐
−√𝟐
𝟐
−𝟐
√𝟑
𝟑
−𝟏 −𝟏
𝐭𝐚𝐧 𝜽 = −𝟐√𝟏𝟎
𝟑
𝐜𝐨𝐭 𝜽 =𝟓
𝟏𝟐
𝐬𝐢𝐧 𝒙 = −√𝟓
𝟑
𝐜𝐨𝐭 𝒙 = −𝟐√𝟏𝟎
𝟑
Pre-Calc Trig ~2~ NJCTL.org
Unit Circle – Home Work
Find the exact value of the given expression.
11. 𝑐𝑜𝑠5𝜋
3 12. 𝑠𝑖𝑛
3𝜋
4 13. 𝑠𝑒𝑐
4𝜋
3
14. 𝑡𝑎𝑛−7𝜋
6 15. 𝑐𝑜𝑡
13𝜋
4 16. 𝑐𝑠𝑐
−11𝜋
2
17. Given the terminal point (7
25,
−24
25) find cotθ
18. Given the terminal point (−4√2
9,
7
9) find tanθ
19. Knowing sinx=7
8 and the terminal point is in the second quadrant find secx.
20. Knowing cscx=−4
5 and the terminal point is in the third quadrant find cotx.
𝟏
𝟐 √𝟐
𝟐
−𝟐
−√𝟑
𝟑
𝟏 𝟏
𝐜𝐨𝐭 𝜽 = −𝟕
𝟐𝟒
𝐭𝐚𝐧 𝜽 = −𝟕√𝟐
𝟖
𝐬𝐞𝐜 𝒙 = −𝟖√𝟏𝟓
𝟏𝟓
𝐜𝐨𝐭 𝒙 =𝟒
𝟑
Pre-Calc Trig ~3~ NJCTL.org
A: 2 P: 𝝅 PS: −𝝅
𝟑 VS: 1 A: 3 P:
𝝅
𝟐 PS:
𝝅
𝟒 VS: -2
A: 1 P: 𝟑𝝅 PS: −𝝅
𝟔 VS: 3 A: 1 P:
𝟐𝝅
𝟑 PS:
𝟐𝝅
𝟑 VS: -1
A:𝟐
𝟑 P:
𝝅
𝟐 PS:
𝝅
𝟐 VS: 2
Graphing – Class Work
State the amplitude, period, phase shift, and vertical shift for each function. Draw the graph by hand and
then check it with a graphing calculator.
21. 𝑦 = 2 cos (2 (𝑥 +𝜋
3)) + 1 22. 𝑦 = −3 cos(4𝑥 − 𝜋) − 2
23. 𝑦 = sin (2
3(𝑥 +
𝜋
6)) + 3 24. 𝑦 = −1 cos(3𝑥 − 2𝜋) − 1
25. 𝑦 =2
3cos(4𝑥 − 2𝜋) + 2
Pre-Calc Trig ~4~ NJCTL.org
A: 4 P: 𝟒𝝅 PS: 𝝅
𝟑 VS: 2 A: 2 P:
𝝅
𝟐 PS:
𝟑𝝅
𝟒 VS: -3
A: 2 P: 𝟖𝝅 PS: −𝝅
𝟐 VS: 1 A: 1 P:
𝝅
𝟑 PS:
𝝅
𝟑 VS: 1
A: 𝟑
𝟐 P:
𝝅
𝟐 PS:
𝟑𝝅
𝟒 VS: -2
Graphing – Home Work
State the amplitude, period, phase shift, and vertical shift for each function. Draw the graph by hand and
then check it with a graphing calculator.
26. 𝑦 = −4 cos (1
2(𝑥 −
𝜋
3)) + 2 27. 𝑦 = −2 cos(4𝑥 − 3𝜋) − 3
28. 𝑦 = 2 sin (1
4(𝑥 +
𝜋
2)) + 1 29. 𝑦 = −1 cos(6𝑥 − 2𝜋) − 1
30. 𝑦 =3
2cos(4𝑥 − 3𝜋) − 2
Pre-Calc Trig ~5~ NJCTL.org
Law of Sines – Class Work
Solve triangle ABC.
31. 𝐴 = 70°, 𝐵 = 30°, 𝑐 = 4 32. 𝐵 = 65°, 𝐶 = 50°, 𝑎 = 12
33. 𝑏 = 6, 𝐴 = 25°, 𝐵 = 45° 34. 𝑐 = 8, 𝐵 = 60°, 𝐶 = 40°
35. 𝑐 = 12, 𝑏 = 6, 𝐶 = 70° 36. 𝑏 = 12, 𝑎 = 15, 𝐵 = 40°
37. 𝐴 = 35°, 𝑎 = 6, 𝑏 = 11
38. An airplane is on the radar at both Newark Liberty International and JFK airports that are 20 miles
apart. The angle of elevation from Newark to the plane is 42°and from JFK is 35° when the plane is
directly between them. How far is the plane from JFK? What is the plane’s elevation?
39. A mathematician walking in the woods noticed that the angle the angle of elevation to a bird at the
top of a tree is 50°, after walking 40’ toward the tree, the angle is 55°. How far is she from the bird?
𝑪 = 𝟖𝟎𝒐 𝒂 = 𝟑. 𝟖𝟐 𝒃 = 𝟐. 𝟎𝟑 𝑨 = 𝟔𝟓𝒐 𝒃 = 𝟏𝟐 𝒄 = 𝟏𝟎. 𝟏𝟒
𝑪 = 𝟏𝟏𝟎𝒐 𝒂 = 𝟑. 𝟓𝟗 𝒄 = 𝟕. 𝟗𝟕 𝑨 = 𝟖𝟎𝒐 𝒂 = 𝟏𝟐. 𝟐𝟔 𝒃 = 𝟏𝟎. 𝟕𝟖
𝑨 = 𝟖𝟐𝒐 𝑩 = 𝟐𝟖𝒐 𝒂 = 𝟏𝟐. 𝟔𝟓 𝑨 = 𝟓𝟑. 𝟓𝒐 𝑪 = 𝟖𝟔. 𝟓𝒐 𝒄 = 𝟏𝟖. 𝟔𝟑
𝒐𝒓
𝑨 = 𝟏𝟐𝟔. 𝟓𝒐 𝑪 = 𝟏𝟑. 𝟓𝒐 𝒄 = 𝟒. 𝟑𝟔
𝑵𝒐 𝑺𝒐𝒍𝒖𝒕𝒊𝒐𝒏
𝟏𝟑. 𝟕𝟑 𝒎𝒊𝒍𝒆𝒔 𝒇𝒓𝒐𝒎 𝑱𝑭𝑲
𝟗. 𝟒𝟏 𝒎𝒊𝒍𝒆𝒔 𝒊𝒏 𝒆𝒍𝒆𝒗𝒂𝒕𝒊𝒐𝒏
𝟑𝟓𝟏. 𝟓𝟕 𝒇𝒆𝒆𝒕 𝒇𝒓𝒐𝒎 𝒕𝒉𝒆 𝒃𝒊𝒓𝒅
Pre-Calc Trig ~6~ NJCTL.org
Law of Sines – Home Work
Solve triangle ABC.
40. 𝐴 = 60°, 𝐵 = 40°, 𝑐 = 5 41. 𝐵 = 75°, 𝐶 = 50°, 𝑎 = 14
42. 𝑏 = 6, 𝐴 = 35°, 𝐵 = 45° 43. 𝑐 = 8, 𝐵 = 50°, 𝐶 = 40°
44. 𝑐 = 12, 𝑏 = 8, 𝐶 = 65° 45. 𝑏 = 12, 𝑎 = 16, 𝐵 = 50°
46. 𝐴 = 40°, 𝑎 = 5, 𝑏 = 12
47. An airplane is on the radar at both Newark Liberty International and JFK airports that are 20 miles
apart. The angle of elevation from Newark to the plane is 52°and from JFK is 45° when the plane is
directly between them. How far is the plane from JFK? What is the plane’s elevation?
48. A mathematician walking in the woods noticed that the angle the angle of elevation to a bird at the
top of a tree is 45°, after walking 30’ toward the tree, the angle is 60°. How far is she from the bird?
𝑪 = 𝟖𝟎𝒐 𝒂 = 𝟒. 𝟒 𝒃 = 𝟑. 𝟐𝟔 𝑨 = 𝟓𝟓𝒐 𝒃 = 𝟏𝟔. 𝟓𝟏 𝒃 = 𝟏𝟑. 𝟎𝟗
𝑪 = 𝟏𝟎𝟎𝒐 𝒂 = 𝟒. 𝟖𝟕 𝒄 = 𝟖. 𝟑𝟔 𝑨 = 𝟗𝟎𝒐 𝒂 = 𝟏𝟐. 𝟒𝟓 𝒃 = 𝟗. 𝟓𝟑
𝑨 = 𝟕𝟕. 𝟖𝒐 𝑩 = 𝟑𝟕. 𝟐𝒐 𝒂 = 𝟏𝟐. 𝟗𝟒 𝑵𝒐 𝑺𝒐𝒍𝒖𝒕𝒊𝒐𝒏
𝑵𝒐 𝑺𝒐𝒍𝒖𝒕𝒊𝒐𝒏
𝟏𝟓. 𝟖𝟖 𝒎𝒊𝒍𝒆𝒔 𝒇𝒓𝒐𝒎 𝑱𝑭𝑲
𝟏𝟐. 𝟑𝟒 𝒎𝒊𝒍𝒆𝒔 𝒊𝒏 𝒆𝒍𝒆𝒗𝒂𝒕𝒊𝒐𝒏
𝟖𝟏. 𝟗𝟔 𝒇𝒆𝒆𝒕 𝒇𝒓𝒐𝒎 𝒕𝒉𝒆 𝒃𝒊𝒓𝒅
Pre-Calc Trig ~7~ NJCTL.org
Law of Cosines – Class Work
Solve triangle ABC.
49. 𝑎 = 3, 𝑏 = 4, 𝑐 = 6 50. 𝑎 = 5, 𝑏 = 6, 𝑐 = 7
51. 𝑎 = 7, 𝑏 = 6, 𝑐 = 4 52. 𝐴 = 100°, 𝑏 = 4, 𝑐 = 5
53. 𝐵 = 60°, 𝑎 = 5, 𝑐 = 9 54. 𝐶 = 40°, 𝑎 = 10, 𝑏 = 12
55. A ship at sea noticed two lighthouses that according to the charts are 1 mile apart. The light at
lighthouse A is 200’ above sea level and the navigator on the ship measures the angle of elevation
to be 2°, how far is the ship from lighthouse A? The light at lighthouse B is 300’ above sea level and
the navigator on the ship measures the angle of elevation to be 5°, how far is the ship from
lighthouse B? How far is the ship from shore?
56. A student takes his 2 dogs for a walk. He lets them off their leash in a field where Edison runs at 7
m/s and Einstein runs at 6 m/s. The student determines the angle between the dogs is 20°, how far
are the dogs from each other in 8 seconds?
𝑨 = 𝟐𝟔. 𝟒𝒐 𝑩 = 𝟑𝟔. 𝟒𝒐 𝑪 = 𝟏𝟏𝟕. 𝟐𝒐
𝒂 = 𝟔. 𝟗𝟐 𝑩 = 𝟑𝟒. 𝟕𝒐 𝑪 = 𝟒𝟓. 𝟑𝒐
𝑨 = 𝟑𝟑. 𝟕𝒐 𝒃 = 𝟕. 𝟖𝟏 𝑪 = 𝟖𝟔. 𝟑𝒐 𝑨 = 𝟓𝟔. 𝟑𝒐 𝑩 = 𝟖𝟑. 𝟕𝒐 𝒄 = 𝟕. 𝟕𝟔
𝑻𝒉𝒆 𝒔𝒉𝒊𝒑 𝒊𝒔 𝟓𝟕𝟐𝟕. 𝟐𝟓 𝒇𝒕 𝒇𝒓𝒐𝒎 𝒍𝒊𝒈𝒉𝒕𝒉𝒐𝒖𝒔𝒆 𝑨
𝑻𝒉𝒆 𝒔𝒉𝒊𝒑 𝒊𝒔 𝟑𝟒𝟐𝟗. 𝟎𝟐 𝒇𝒕 𝒇𝒓𝒐𝒎 𝒍𝒊𝒈𝒉𝒕𝒉𝒐𝒖𝒔𝒆 𝑩
𝑻𝒉𝒆 𝒔𝒉𝒊𝒑 𝒊𝒔 𝟑𝟑𝟔𝟔. 𝟒 𝒇𝒕 𝒇𝒓𝒐𝒎 𝒔𝒉𝒐𝒓𝒆
𝑻𝒉𝒆 𝒅𝒐𝒈𝒔 𝒂𝒓𝒆 𝟏𝟗. 𝟕 𝒎 𝒂𝒑𝒂𝒓𝒕
𝑨 = 𝟒𝟒. 𝟒𝒐 𝑩 = 𝟓𝟕. 𝟏𝒐 𝑪 = 𝟕𝟖. 𝟓𝒐
𝑨 = 𝟖𝟔. 𝟒𝒐 𝑩 = 𝟓𝟖. 𝟖𝒐 𝑪 = 𝟑𝟒. 𝟖𝒐
Pre-Calc Trig ~8~ NJCTL.org
Law of Cosines – Home Work
Solve triangle ABC.
57. 𝑎 = 4, 𝑏 = 5, 𝑐 = 8 58. 𝑎 = 4, 𝑏 = 10, 𝑐 = 13
59. 𝑎 = 11, 𝑏 = 8, 𝑐 = 6 60. 𝐴 = 85°, 𝑏 = 3, 𝑐 = 7
61. 𝐵 = 70°, 𝑎 = 6, 𝑐 = 12 62. 𝐶 = 25°, 𝑎 = 14, 𝑏 = 19
63. A ship at sea noticed two lighthouses that according to the charts are 1 mile apart. The light at
lighthouse A is 275’ above sea level and the navigator on the ship measures the angle of elevation
to be 4°, how far is the ship from lighthouse A? The light at lighthouse B is 325’ above sea level and
the navigator on the ship measures the angle of elevation to be 8°, how far is the ship from
lighthouse B? How far is the ship from shore?
64. A student takes his 2 dogs for a walk. He lets them off their leash in a field where Edison runs at 10
m/s and Einstein runs at 8 m/s. The student determines the angle between the dogs is 25°, how far
are the dogs from each other in 5 seconds?
𝑨 = 𝟐𝟒. 𝟏𝒐 𝑩 = 𝟑𝟎. 𝟕𝒐 𝑪 = 𝟏𝟐𝟓. 𝟐𝒐 𝑨 = 𝟏𝟑. 𝟑𝒐 𝑩 = 𝟑𝟓. 𝟏𝒐 𝑪 = 𝟏𝟑𝟏. 𝟔𝒐
𝑨 = 𝟏𝟎𝟐. 𝟔𝒐 𝑩 = 𝟒𝟓. 𝟐𝒐 𝑪 = 𝟑𝟐. 𝟐𝒐 𝒂 = 𝟕. 𝟑𝟕 𝑩 = 𝟐𝟑. 𝟗𝒐 𝑪 = 𝟕𝟏. 𝟏𝒐
𝑨 = 𝟐𝟗. 𝟔𝒐 𝒃 = 𝟏𝟏. 𝟒𝟑 𝑪 = 𝟖𝟎. 𝟒𝒐 𝑨 = 𝟖𝟔. 𝟖𝒐 𝑩 = 𝟔𝟖. 𝟐𝒐 𝒄 = 𝟖. 𝟔𝟓
𝑻𝒉𝒆 𝒔𝒉𝒊𝒑 𝒊𝒔 𝟑𝟗𝟑𝟐. 𝟕 𝒇𝒕 𝒇𝒓𝒐𝒎 𝒍𝒊𝒈𝒉𝒕𝒉𝒐𝒖𝒔𝒆 𝑨
𝑻𝒉𝒆 𝒔𝒉𝒊𝒑 𝒊𝒔 𝟐𝟑𝟏𝟐. 𝟓 𝒇𝒕 𝒇𝒓𝒐𝒎 𝒍𝒊𝒈𝒉𝒕𝒉𝒐𝒖𝒔𝒆 𝑩
𝑻𝒉𝒆 𝒔𝒉𝒊𝒑 𝒊𝒔 𝟏𝟓𝟖𝟕. 𝟎 𝒇𝒕 𝒇𝒓𝒐𝒎 𝒔𝒉𝒐𝒓𝒆
𝑻𝒉𝒆 𝒅𝒐𝒈𝒔 𝒂𝒓𝒆 𝟐𝟏. 𝟖 𝒎 𝒂𝒑𝒂𝒓𝒕
Pre-Calc Trig ~9~ NJCTL.org
Pythagorean Identities – Class Work
Simplify the expression
65. csc 𝑥 tan 𝑥 66. cot 𝑥 sec 𝑥 sin 𝑥
67. sin x (csc x − sin x) 68. (1 + cot2x)(1 − cos2x)
69. 1 −tan2x
sec2𝑥 70. (sin x − cos x)2
71. cot2x
1−sin2x 72.
cosx
secx+tanx
73. sin 𝑥 tan 𝑥 + cos 𝑥
Verify the Identity
74. (1 − sin 𝑥)(1 + sin 𝑥) = cos2 x 75. tan 𝑥 cot 𝑥
sec 𝑥= cos 𝑥
76. (1 − cos2x)(1 + tan2x) = tan2x 77. 1
sec x+tan x+
1
sec x−tan x= 2 sec x
𝐬𝐞𝐜 𝒙 𝟏
𝐜𝐨𝐬𝟐 𝒙 𝟏
𝐜𝐨𝐬𝟐 𝒙 𝟏 − 𝐬𝐢𝐧 𝟐𝒙
𝐜𝐬𝐜𝟐 𝒙 𝟏 − 𝐬𝐢𝐧 𝒙
𝐬𝐞𝐜 𝒙
𝟏 − 𝐬𝐢𝐧𝟐 𝒙
𝐜𝐨𝐬𝟐 𝒙
𝟏
𝐬𝐞𝐜 𝒙
𝐜𝐨𝐬 𝒙
(𝐬𝐢𝐧𝟐 𝒙)(𝐬𝐞𝐜𝟐 𝒙)
(𝐬𝐢𝐧𝟐 𝒙) (𝟏
𝐜𝐨𝐬𝟐 𝒙)
𝐭𝐚𝐧𝟐 𝒙
(𝐬𝐞𝐜 𝒙−𝐭𝐚𝐧 𝒙)+(𝐬𝐞𝐜 𝒙+𝐭𝐚𝐧 𝒙)
𝐬𝐞𝐜𝟐 𝒙−𝐭𝐚𝐧𝟐 𝒙
𝟐 𝐬𝐞𝐜 𝒙
𝟏
𝟐 𝐬𝐞𝐜 𝒙
Pre-Calc Trig ~10~ NJCTL.org
Pythagorean Identities – Home Work
Simplify the expression
78. (tan x + cot x )2 79. 1−sin x
cos x+
cos x
1−sin x
80. cos x−cos y
sin x+sin y+
sin x−sin y
cos x+cos y 81.
1
sin 𝑥−
1
csc 𝑥
82. 1+sec2x
1+tan2x 83.
sin2x
tan2x+
cos2x
cot2x
84. 𝑡𝑎𝑛2𝑥
1+𝑡𝑎𝑛2𝑥 85.
cos x
sec x+
sin x
csc x
86. 1+sec2x
1+tan2x+
cos2x
cot2x
Verify the Identity
87. 𝑐𝑜𝑠2𝑥 − 𝑠𝑖𝑛2𝑥 = 1 − 2𝑠𝑖𝑛2𝑥 88. tan 𝑥 cos 𝑥 csc 𝑥 = 1
89. 1+cot x
csc x= sin x + cos x 90.
cos x csc x
cot x= 1
𝐬𝐞𝐜𝟐 𝒙 + 𝐜𝐬𝐜𝟐 𝒙 𝟐 𝐬𝐞𝐜 𝒙
𝟎 𝐜𝐨𝐬 𝒙 𝐜𝐨𝐭 𝒙
𝐜𝐨𝐬𝟐 𝒙 + 𝟏 𝟏
𝐬𝐢𝐧𝟐 𝒙 𝟏
𝟐
(𝟏 − 𝐬𝐢𝐧𝟐 𝒙) − 𝐬𝐢𝐧𝟐 𝒙
𝟏 − 𝟐 𝐬𝐢𝐧𝟐 𝒙
(𝐬𝐢𝐧 𝒙
𝐜𝐨𝐬 𝒙) (𝐜𝐨𝐬 𝒙) (
𝟏
𝐬𝐢𝐧 𝒙)
𝟏
𝟏+𝐜𝐨𝐬 𝒙
𝐬𝐢𝐧 𝒙𝟏
𝐬𝐢𝐧 𝒙
(𝟏 +𝐜𝐨𝐬 𝒙
𝐬𝐢𝐧 𝒙) (
𝐬𝐢𝐧 𝒙
𝟏)
𝐬𝐢𝐧 𝒙 + 𝐜𝐨𝐬 𝒙
𝐜𝐨𝐬 𝒙𝟏
𝐬𝐢𝐧 𝒙𝐜𝐨𝐬 𝒙
𝐬𝐢𝐧 𝒙
𝐜𝐨𝐬 𝒙
𝐬𝐢𝐧 𝒙∙
𝐬𝐢𝐧 𝒙
𝐜𝐨𝐬 𝒙
𝟏
Pre-Calc Trig ~11~ NJCTL.org
Angle Sum/Difference Identity – Class Work
Use Angle Sum/Difference Identity to find the exact value of the expression.
91. sin 105 92. cos 75
93. tan 195 94. 𝑠𝑖𝑛 −𝜋
12
95. cos19𝜋
12 96. 𝑡𝑎𝑛 −
𝜋
12
Verify the Identity.
97. sin (𝑥 +𝜋
3) + sin (𝑥 −
𝜋
3) = sin 𝑥 98. cos (𝑥 +
𝜋
4) cos (𝑥 −
𝜋
4) = cos2 𝑥 −
1
2
99. tan (𝑥 −𝜋
4) =
tan 𝑥−1
tan 𝑥+1 100.
sin(𝑥+𝑦)−sin(𝑥−𝑦)
cos(𝑥+𝑦)+cos(𝑥−𝑦)= tan 𝑦
√𝟔 + √𝟐
𝟒
√𝟔 − √𝟐
𝟒
−𝟏 + √𝟑
𝟏 + √𝟑
√𝟐 − √𝟔
𝟒
√𝟔 − √𝟐
𝟒
𝟏 − √𝟑
𝟏 + √𝟑
𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬𝝅
𝟑+ 𝐜𝐨𝐬 𝒙 𝐬𝐢𝐧
𝝅
𝟑+ 𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬
𝝅
𝟑− 𝐜𝐨𝐬 𝒙 𝐬𝐢𝐧
𝝅
𝟑
𝐬𝐢𝐧 𝒙 ∗𝟏
𝟐+ 𝐬𝐢𝐧 𝒙 ∗
𝟏
𝟐
𝐬𝐢𝐧 𝒙
(𝐜𝐨𝐬 𝒙 𝐜𝐨𝐬𝝅
𝟒− 𝐬𝐢𝐧 𝒙 𝐬𝐢𝐧
𝝅
𝟒) (𝐜𝐨𝐬 𝒙 𝐜𝐨𝐬
𝝅
𝟒+ 𝐬𝐢𝐧 𝒙 𝐬𝐢𝐧
𝝅
𝟒)
(𝐜𝐨𝐬 𝒙 ∗√𝟐
𝟐− 𝐬𝐢𝐧 𝒙 ∗
√𝟐
𝟐) (𝐜𝐨𝐬 𝒙 ∗
√𝟐
𝟐+ 𝐬𝐢𝐧 𝒙 ∗
√𝟐
𝟐)
𝟐
𝟒𝐜𝐨𝐬𝟐 𝒙 −
𝟐
𝟒𝐬𝐢𝐧𝟐 𝒙
𝟏
𝟐𝐜𝐨𝐬𝟐 𝒙 −
𝟏
𝟐(𝟏 − 𝐜𝐨𝐬𝟐 𝒙)
𝐜𝐨𝐬𝟐 𝒙 −𝟏
𝟐
𝐭𝐚𝐧 𝒙−𝐭𝐚𝐧𝝅
𝟒
𝟏+𝐭𝐚𝐧 𝒙 𝐭𝐚𝐧𝝅
𝟒
𝐭𝐚𝐧 𝒙−𝟏
𝟏+𝐭𝐚𝐧 𝒙(𝟏)
(𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬 𝒚+𝐜𝐨𝐬 𝒙 𝐬𝐢𝐧 𝒚)−(𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬 𝒚−𝐜𝐨𝐬 𝒙 𝐬𝐢𝐧 𝒚)
(𝐜𝐨𝐬 𝒙 𝐜𝐨𝐬 𝒚−𝐬𝐢𝐧 𝒙 𝐬𝐢𝐧 𝒚)+(𝐜𝐨𝐬 𝒙 𝐜𝐨𝐬 𝒚+𝐬𝐢𝐧 𝒙 𝐬𝐢𝐧 𝒚)
𝟐 𝐜𝐨𝐬 𝒙 𝐬𝐢𝐧 𝒚
𝟐 𝐜𝐨𝐬 𝒙 𝐜𝐨𝐬 𝒚
𝐭𝐚𝐧 𝒚
Pre-Calc Trig ~12~ NJCTL.org
Angle Sum/Difference Identity – Home Work
Use Angle Sum/Difference Identity to find the exact value of the expression.
101. sin 165 102. cos 105
103. tan 285 104. 𝑠𝑖𝑛 −11𝜋
12
105. cos17𝜋
12 106. 𝑡𝑎𝑛 −
7𝜋
12
Verify the Identity.
107. sin (𝑥 +2𝜋
3) + sin (𝑥 −
2𝜋
3) = −sin 𝑥 108. cos (𝑥 +
3𝜋
4) cos (𝑥 −
3𝜋
4) = cos2 𝑥 −
1
2
109. tan (𝑥 +5𝜋
4) =
tan 𝑥+1
1−tan 𝑥 110. 𝑐𝑜𝑠 (
5𝜋
6+ 𝑥) 𝑐𝑜𝑠 (
5𝜋
6− 𝑥) =
3
4− sin2 𝑥
√𝟔 − √𝟐
𝟒
√𝟐 − √𝟔
𝟒
𝟏 + √𝟑
𝟏 − √𝟑
√𝟐 − √𝟔
𝟒
√𝟐 − √𝟔
𝟒
−𝟏 + √𝟑
𝟏 − √𝟑
(𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬𝟐𝝅
𝟑+ 𝐜𝐨𝐬 𝒙 𝐬𝐢𝐧
𝟐𝝅
𝟑) + (𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬
𝟐𝝅
𝟑− 𝐜𝐨𝐬 𝒙 𝐬𝐢𝐧
𝟐𝝅
𝟑)
𝐬𝐢𝐧 𝒙 ∗ −𝟏
𝟐+ 𝐬𝐢𝐧 𝒙 ∗ −
𝟏
𝟐
− 𝐬𝐢𝐧 𝒙
(𝐜𝐨𝐬 𝒙 𝐜𝐨𝐬𝟑𝝅
𝟒− 𝐬𝐢𝐧 𝒙 𝐬𝐢𝐧
𝟑𝝅
𝟒) (𝐜𝐨𝐬 𝒙 𝐜𝐨𝐬
𝟑𝝅
𝟒+ 𝐬𝐢𝐧 𝒙 𝐬𝐢𝐧
𝟑𝝅
𝟒)
(𝐜𝐨𝐬 𝒙 ∗−√𝟐
𝟐− 𝐬𝐢𝐧 𝒙 ∗
√𝟐
𝟐) (𝐜𝐨𝐬 𝒙 ∗
−√𝟐
𝟐+ 𝐬𝐢𝐧 𝒙 ∗
√𝟐
𝟐)
𝟐
𝟒𝐜𝐨𝐬𝟐 𝒙 −
𝟐
𝟒𝐬𝐢𝐧𝟐 𝒙
𝟏
𝟐𝐜𝐨𝐬𝟐 𝒙 −
𝟏
𝟐(𝟏 − 𝐜𝐨𝐬𝟐 𝒙)
𝐜𝐨𝐬𝟐 𝒙 −𝟏
𝟐
𝐭𝐚𝐧 𝒙+𝐭𝐚𝐧𝟓𝝅
𝟒
𝟏−𝐭𝐚𝐧 𝒙 𝐭𝐚𝐧𝟓𝝅
𝟒
𝐭𝐚𝐧 𝒙+𝟏
𝟏−𝐭𝐚𝐧 𝒙(𝟏)
(𝐜𝐨𝐬𝟓𝝅
𝟔𝐜𝐨𝐬 𝒙 − 𝐬𝐢𝐧
𝟓𝝅
𝟔𝐬𝐢𝐧 𝒙) (𝐜𝐨𝐬
𝟓𝝅
𝟔𝐜𝐨𝐬 𝒙 + 𝐬𝐢𝐧
𝟓𝝅
𝟔𝐬𝐢𝐧 𝒙)
(−√𝟑
𝟐∗ 𝐜𝐨𝐬 𝒙 −
𝟏
𝟐∗ 𝐬𝐢𝐧 𝒙) (
−√𝟑
𝟐∗ 𝐜𝐨𝐬 𝒙 +
𝟏
𝟐∗ 𝐬𝐢𝐧 𝒙)
𝟑
𝟒𝐜𝐨𝐬𝟐 𝒙 −
𝟏
𝟒𝐬𝐢𝐧𝟐 𝒙
𝟑
𝟒(𝟏 − 𝐬𝐢𝐧𝟐 𝒙) −
𝟏
𝟒𝐬𝐢𝐧𝟐 𝒙
𝟑
𝟒− 𝐬𝐢𝐧𝟐 𝒙
Pre-Calc Trig ~13~ NJCTL.org
Double Angle Identity – Class Work
Find the exact value of the expression.
111. 𝑐𝑜𝑠𝜃 =1
4, 𝑓𝑖𝑛𝑑 cos 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑓𝑖𝑟𝑠𝑡 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
112. 𝑐𝑜𝑠𝜃 =1
4, 𝑓𝑖𝑛𝑑 sin 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑓𝑜𝑢𝑟𝑡ℎ 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
113. 𝑠𝑖𝑛𝜃 =−3
7, 𝑓𝑖𝑛𝑑 tan 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑡ℎ𝑖𝑟𝑑 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
114. 𝑠𝑖𝑛𝜃 =−3
7, 𝑓𝑖𝑛𝑑 cos 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑓𝑜𝑢𝑟𝑡ℎ 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
115. 𝑡𝑎𝑛𝜃 =−5
9, 𝑓𝑖𝑛𝑑 sin 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑠𝑒𝑐𝑜𝑛𝑑 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
116. 𝑐𝑜𝑡𝜃 =5
9, 𝑓𝑖𝑛𝑑 tan 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑡ℎ𝑖𝑟𝑑 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
Verify the Identity.
117. sin 3𝑥 = 3 sin 𝑥 − 4 sin3 𝑥 118. tan 3𝑥 =3 tan 𝑥−𝑡𝑎𝑛3𝑥
1−3𝑡𝑎𝑛2𝑥
118.
119. sin 4𝑥
sin 𝑥= 4 cos 2𝑥 𝑐𝑜𝑠 𝑥 120. csc 2𝑥 =
csc 𝑥
2 cos 𝑥
−𝟕
𝟖
−√𝟏𝟓
𝟖
𝟏𝟐√𝟏𝟎
𝟑𝟏
−𝟑𝟏
𝟒𝟗
−𝟒𝟓
𝟓𝟑
−𝟒𝟓
𝟐𝟖
𝐬𝐢𝐧(𝟐𝒙 + 𝒙)
𝐬𝐢𝐧 𝟐𝒙 𝐜𝐨𝐬 𝒙 + 𝐜𝐨𝐬 𝟐𝒙 𝐬𝐢𝐧 𝒙
(𝟐 𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬 𝒙) 𝐜𝐨𝐬 𝒙 + (𝟏 − 𝟐 𝐬𝐢𝐧𝟐 𝒙) 𝐬𝐢𝐧 𝒙
𝟐 𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬𝟐 𝒙 + 𝐬𝐢𝐧 𝒙 − 𝟐 𝐬𝐢𝐧𝟑 𝒙
𝟐 𝐬𝐢𝐧 𝒙 (𝟏 − 𝐬𝐢𝐧𝟐 𝒙) + 𝐬𝐢𝐧 𝒙 − 𝟐 𝐬𝐢𝐧𝟑 𝒙
𝟑 𝐬𝐢𝐧 𝒙 − 𝟒 𝐬𝐢𝐧𝟑 𝒙
𝐭𝐚𝐧(𝟐𝒙 + 𝒙)
𝐭𝐚𝐧 𝟐𝒙+𝐭𝐚𝐧 𝒙
𝟏−𝐭𝐚𝐧 𝟐𝒙 𝐭𝐚𝐧 𝒙
𝟐 𝐭𝐚𝐧 𝒙
𝟏−𝐭𝐚𝐧𝟐 𝒙+𝐭𝐚𝐧 𝒙
𝟏−𝟐 𝐭𝐚𝐧 𝒙
𝟏−𝐭𝐚𝐧𝟐 𝒙𝐭𝐚𝐧 𝒙
𝟐 𝐭𝐚𝐧 𝒙+𝐭𝐚𝐧 𝒙−𝐭𝐚𝐧𝟑 𝒙
𝟏−𝐭𝐚𝐧𝟐 𝒙
𝟏−𝐭𝐚𝐧𝟐 𝒙−𝟐 𝐭𝐚𝐧𝟐 𝒙
𝟏−𝐭𝐚𝐧𝟐 𝒙
→𝟑 𝐭𝐚𝐧 𝒙−𝐭𝐚𝐧𝟑 𝒙
𝟏−𝟑 𝐭𝐚𝐧𝟐 𝒙
𝟐 𝐬𝐢𝐧 𝟐𝒙 𝐜𝐨𝐬 𝟐𝒙
𝐬𝐢𝐧 𝒙
𝟐(𝟐 𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬 𝒙) 𝐜𝐨𝐬 𝟐𝒙
𝐬𝐢𝐧 𝒙
𝟒 𝐜𝐨𝐬 𝒙 𝐜𝐨𝐬 𝟐𝒙
𝟏
𝐬𝐢𝐧 𝟐𝒙
𝟏
𝟐 𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬 𝒙
𝟏
𝐬𝐢𝐧 𝒙∗
𝟏
𝟐 𝐜𝐨𝐬 𝒙→
𝐜𝐬𝐜 𝒙
𝟐 𝐜𝐨𝐬 𝒙
Pre-Calc Trig ~14~ NJCTL.org
Double Angle Identity – Home Work
Find the exact value of the expression.
121. 𝑐𝑜𝑠𝜃 =3
4, 𝑓𝑖𝑛𝑑 cos 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑓𝑖𝑟𝑠𝑡 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
122. 𝑐𝑜𝑠𝜃 =3
4, 𝑓𝑖𝑛𝑑 sin 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑓𝑜𝑢𝑟𝑡ℎ 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
123. 𝑠𝑖𝑛𝜃 =−5
7, 𝑓𝑖𝑛𝑑 tan 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑡ℎ𝑖𝑟𝑑 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
124. 𝑠𝑖𝑛𝜃 =−5
7, 𝑓𝑖𝑛𝑑 cos 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑓𝑜𝑢𝑟𝑡ℎ 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
125. 𝑡𝑎𝑛𝜃 =−4
9, 𝑓𝑖𝑛𝑑 sin 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑠𝑒𝑐𝑜𝑛𝑑 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
126. 𝑐𝑜𝑡𝜃 =4
9, 𝑓𝑖𝑛𝑑 tan 2𝜃 𝑖𝑓 𝜃 𝑖𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑡ℎ𝑖𝑟𝑑 𝑞𝑢𝑎𝑑𝑟𝑎𝑛𝑡.
Verify the Identity.
127. sec 2𝑥 =sec2 𝑥
2−sec2 𝑥 128.
1+sin 2x
sin 2x= 1 +
1
2sec x cscx
129. 1 + cos 10𝑥 = 2 cos2 5𝑥
𝟏
𝟖
−𝟑√𝟕
𝟖
−𝟐𝟎√𝟔
−𝟏
𝟒𝟗
−𝟕𝟐
𝟗𝟕
−𝟕𝟐
𝟔𝟓
𝟏
𝐜𝐨𝐬 𝟐𝒙
𝟏
𝟐 𝐜𝐨𝐬𝟐 𝒙−𝟏
𝟏
𝐜𝐨𝐬𝟐 𝒙
𝟐 𝐜𝐨𝐬𝟐 𝒙−𝟏
𝐜𝐨𝐬𝟐 𝒙
𝐬𝐞𝐜𝟐 𝒙
𝟐−𝐬𝐞𝐜𝟐 𝒙
𝟏
𝐬𝐢𝐧 𝟐𝒙+ 𝟏
𝟏
𝟐 𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬 𝒙+ 𝟏
𝟏
𝟐𝐜𝐬𝐜 𝒙 𝐬𝐞𝐜 𝒙 + 𝟏
𝟏 + (𝟐 𝐜𝐨𝐬𝟐 𝟓𝒙 − 𝟏)
𝟐 𝐜𝐨𝐬𝟐 𝟓𝒙
Pre-Calc Trig ~15~ NJCTL.org
Half Angle Identity – Class Work
Find the exact value of the expression.
130. √1−cos 6𝑥
2 131. cos2 (
𝑥
2) − sin2 (
𝑥
2)
132. sin 22.5 133. tan 67.5
Verify the Identity.
134. sec𝑥
2= ±√
2𝑡𝑎𝑛𝑥
tan 𝑥+sin 𝑥
Half Angle Identity – Home Work
Find the exact value of the expression.
135. √1+cos 4𝑥
2 136. 2 cos (
𝑥
2) sin (
𝑥
2)
137. cos 22.5 138. tan 15
Verify the Identity.
139. tan𝑥
2= csc 𝑥 − cot 𝑥
𝐬𝐢𝐧 𝟑𝒙 𝐜𝐨𝐬 𝟐𝒙
√𝟐 − √𝟐
𝟐
√𝟐
𝟐 − √𝟐 𝒐𝒓
𝟐 + √𝟐
𝟐
= √𝟐
𝐬𝐢𝐧 𝒙
𝐜𝐨𝐬 𝒙𝐬𝐢𝐧 𝒙
𝐜𝐨𝐬 𝒙+𝐬𝐢𝐧 𝒙
→ √𝟐 𝐬𝐢𝐧 𝒙
𝐜𝐨𝐬 𝒙𝐬𝐢𝐧 𝒙+𝐬𝐢𝐧 𝒙 𝐜𝐨𝐬 𝒙
𝐜𝐨𝐬 𝒙
→ √𝟐 𝐬𝐢𝐧 𝒙
𝐜𝐨𝐬 𝒙∗
𝐜𝐨𝐬 𝒙
𝐬𝐢𝐧 𝒙(𝟏+𝐜𝐨𝐬 𝒙) →
√𝟐
𝟏+𝐜𝐨𝐬 𝒙 →
𝟏
√𝟏+𝐜𝐨𝐬 𝒙
𝟐
→ 𝟏
𝐜𝐨𝐬𝒙
𝟐
→ 𝐬𝐞𝐜𝒙
𝟐
𝐜𝐨𝐬 𝟐𝒙 𝐬𝐢𝐧 𝒙
√𝟐 + √𝟐
𝟐
𝟏
𝟐 + √𝟑 𝒐𝒓 𝟐 − √𝟑
=𝟏−𝐜𝐨𝐬 𝒙
𝐬𝐢𝐧 𝒙 →
𝟏
𝐬𝐢𝐧 𝒙−
𝐜𝐨𝐬 𝒙
𝐬𝐢𝐧 𝒙 → 𝐜𝐬𝐜 𝒙 − 𝐜𝐨𝐭 𝒙
Pre-Calc Trig ~16~ NJCTL.org
Power Reducing Identity – Class Work
Simplify the expression.
140. 𝑐𝑜𝑠4𝑥 141. 𝑠𝑖𝑛8𝑥
142. 𝑠𝑖𝑛4𝑥 𝑐𝑜𝑠2𝑥
143. Find sin𝜃
2 if cos 𝜃 =
3
5 and 𝜃 is in the first quadrant.
144. Find cos𝜃
2 if tan 𝜃 =
3
5 and 𝜃 is in the third quadrant.
𝟑
𝟖+
𝟏
𝟐𝐜𝐨𝐬 𝟐𝒙 +
𝟏
𝟖𝐜𝐨𝐬 𝟒𝒙
𝟑𝟓
𝟏𝟐𝟖−
𝟑
𝟖𝐜𝐨𝐬 𝟐𝒙 +
𝟑
𝟑𝟐𝐜𝐨𝐬 𝟒𝒙 −
𝟏
𝟖𝐜𝐨𝐬 𝟐𝒙 𝐜𝐨𝐬 𝟒𝒙 +
𝟏
𝟏𝟐𝟖𝐜𝐨𝐬 𝟖𝒙
𝟏
𝟏𝟔−
𝟏
𝟏𝟔𝐜𝐨𝐬 𝟐𝒙 −
𝟏
𝟏𝟔𝐜𝐨𝐬 𝟒𝒙 +
𝟏
𝟏𝟔𝐜𝐨𝐬 𝟐𝒙 𝐜𝐨𝐬 𝟒𝒙
√𝟓
𝟓
−√𝟏𝟕(𝟑𝟒−𝟓√𝟑𝟒)
𝟑𝟒
Pre-Calc Trig ~17~ NJCTL.org
Power Reducing Identity – Home Work
Simplify the expression.
145. 𝑠𝑖𝑛2𝑥 𝑐𝑜𝑠2𝑥 146. 𝑠𝑖𝑛4𝑥 𝑐𝑜𝑠4𝑥
147. 𝑠𝑖𝑛2𝑥 𝑐𝑜𝑠4𝑥
148. Find sin𝜃
2 if cos 𝜃 =
3
5 and 𝜃 is in the fourth quadrant.
149. Find cos𝜃
2 if sin 𝜃 =
−4
7 and 𝜃 is in the third quadrant.
𝟏
𝟖−
𝟏
𝟖𝐜𝐨𝐬 𝟒𝒙
𝟑
𝟏𝟐𝟖−
𝟏
𝟑𝟐𝐜𝐨𝐬 𝟒𝒙 +
𝟏
𝟏𝟐𝟖𝐜𝐨𝐬 𝟖𝒙
𝟏
𝟏𝟔+
𝟏
𝟏𝟔𝐜𝐨𝐬 𝟐𝒙 −
𝟏
𝟏𝟔𝐜𝐨𝐬 𝟒𝒙 −
𝟏
𝟏𝟔𝐜𝐨𝐬 𝟐𝒙 𝐜𝐨𝐬 𝟒𝒙
−√𝟓
𝟓
−√𝟏𝟒(𝟕−√𝟑𝟑)
𝟏𝟒
Pre-Calc Trig ~18~ NJCTL.org
Sum to Product Identity – Class Work
Find the exact value of the expression.
150. sin 75 + sin 15 151. cos 75 – cos 15 152. cos 75 + cos 15
Verify the Identity.
153. sin x+ sin5x
cos x+cos5x= tan3x 154.
sin x + sin y
cos x−cos y= − cot
x−y
2 155.
cos x+cos 3x
sin 3x−sin x= cot x
Sum to Product Identity – Home Work
Find the exact value of the expression.
156. sin 105 + sin 15 157. cos 105 – cos 15 158. cos 105 + cos 15
Verify the Identity.
159. cos4x+cos2x
sin 4x+sin2x= cot3x 160.
sin x+sin 5x+sin 3x
cos x+cos 5x+cos 3𝑥= tan 3x
161. cos 87 + cos 33 = sin 63
√𝟔
𝟐
−√𝟐
𝟐
√𝟔
𝟐
√𝟔
𝟐
−√𝟔
𝟐
√𝟐
𝟐
𝟐 𝐬𝐢𝐧𝟔𝒙𝟐 𝐜𝐨𝐬
𝟒𝒙𝟐
𝟐 𝐜𝐨𝐬𝟔𝒙𝟐 𝐜𝐨𝐬
𝟒𝒙𝟐
𝐬𝐢𝐧 𝟑𝒙
𝐜𝐨𝐬 𝟑𝒙
𝐭𝐚𝐧 𝟑𝒙
𝟐 𝐬𝐢𝐧𝒙+𝒚
𝟐𝐜𝐨𝐬
𝒙−𝒚
𝟐
−𝟐 𝐬𝐢𝐧𝒙+𝒚
𝟐𝐬𝐢𝐧
𝒙−𝒚
𝟐
−𝐜𝐨𝐬
𝒙−𝒚
𝟐
𝐬𝐢𝐧𝒙−𝒚
𝟐
−𝐜𝐨𝐭𝒙−𝒚
𝟐
𝟐 𝐜𝐨𝐬𝟒𝒙𝟐 𝐜𝐨𝐬
𝟐𝒙𝟐
𝟐 𝐬𝐢𝐧𝟐𝒙𝟐 𝐜𝐨𝐬
𝟒𝒙𝟐
𝐜𝐨𝐬 𝒙
𝐬𝐢𝐧 𝒙
𝐜𝐨𝐭 𝒙
𝟐 𝐜𝐨𝐬𝟔𝒙
𝟐𝐜𝐨𝐬
𝟐𝒙
𝟐
𝟐 𝐬𝐢𝐧𝟔𝒙
𝟐𝐜𝐨𝐬
𝟐𝒙
𝟐
𝐜𝐨𝐬 𝟑𝒙
𝐬𝐢𝐧 𝟑𝒙
𝐜𝐨𝐭 𝟑𝒙
𝟐 𝐜𝐨𝐬𝟏𝟐𝟎
𝟐𝐜𝐨𝐬
𝟓𝟒
𝟐
𝟐 𝐜𝐨𝐬 𝟔𝟎 𝐜𝐨𝐬 𝟐𝟕
𝟐 ∗𝟏
𝟐∗ 𝐬𝐢𝐧(𝟗𝟎 − 𝟐𝟕)
𝐬𝐢𝐧 𝟔𝟑
𝟐 𝐬𝐢𝐧𝟔𝒙𝟐
𝐜𝐨𝐬−𝟒𝒙
𝟐+ 𝐬𝐢𝐧 𝟑𝒙
𝟐 𝐜𝐨𝐬𝟔𝒙𝟐 𝐜𝐨𝐬
−𝟒𝒙𝟐 + 𝐜𝐨𝐬 𝟑𝒙
𝟐 𝐬𝐢𝐧 𝟑𝒙 𝐜𝐨𝐬(−𝟐𝒙) + 𝐬𝐢𝐧 𝟑𝒙
𝟐 𝐜𝐨𝐬 𝟑𝒙 𝐜𝐨𝐬(−𝟐𝒙) + 𝐜𝐨𝐬 𝟑𝒙
𝐬𝐢𝐧 𝟑𝒙 (𝟐 𝐜𝐨𝐬(−𝟐𝒙) + 𝟏)
𝐜𝐨𝐬 𝟑𝒙 (𝟐 𝐜𝐨𝐬(−𝟐𝒙) + 𝟏)
𝐬𝐢𝐧 𝟑𝒙
𝐜𝐨𝐬 𝟑𝒙
𝐭𝐚𝐧 𝟑𝒙
Pre-Calc Trig ~19~ NJCTL.org
Product to Sum Identity – Class Work
Find the exact value of the expression.
162. cos 75 cos 15 163. sin 37.5 sin 7.5
164. 2 sin 52.5 cos 97.5 165. 10 cos 6𝑥 sin 4𝑥
Product to Sum Identity – Home Work
Find the exact value of the expression.
166. cos 37.5 cos 7.5 167. sin 45 sin 15
168. 4 cos 195 sin 15 169. 3 sin 8𝑥 cos 2𝑥
√𝟐+√𝟑
𝟒
𝟏−√𝟑
𝟒
−𝟏
𝟒
𝟑
𝟐𝐬𝐢𝐧 𝟏𝟎𝒙 +
𝟑
𝟐𝐬𝐢𝐧 𝟔𝒙
𝟏
𝟒
√𝟐−√𝟑
𝟒
𝟏+√𝟐
𝟒
𝟓 𝐬𝐢𝐧 𝟏𝟎𝒙 − 𝟓 𝐬𝐢𝐧 𝟐𝒙
Pre-Calc Trig ~20~ NJCTL.org
Inverse Trig Functions – Class Work
Evaluate the expression.
170. sin (𝑐𝑜𝑠−1 5
13) 170. 𝑐𝑜𝑠 (𝑡𝑎𝑛−1 −
6
5)
171. 𝑡𝑎𝑛 (𝑠𝑖𝑛−1 3
4) 172. sin (𝑡𝑎𝑛−1 −
7
13)
173. 𝑐𝑜𝑠 (𝑠𝑖𝑛−1 6
11) 174. 𝑡𝑎𝑛 (𝑐𝑜𝑠−1 −
3
5)
175. sin−1 (sinπ
4) 176. sin−1 (sin
3π
4)
177. cos−1 (cosπ
3) 178. cos−1 (cos −
π
3)
Inverse Trig Functions – Home Work
Evaluate the expression.
179. sin (𝑐𝑜𝑠−1 12
13) 180. 𝑐𝑜𝑠 (𝑡𝑎𝑛−1 −
7
5)
181. 𝑡𝑎𝑛 (𝑠𝑖𝑛−1 1
4) 182. sin (𝑡𝑎𝑛−1 −
5
13)
183. 𝑐𝑜𝑠 (𝑠𝑖𝑛−1 9
11) 184. 𝑡𝑎𝑛 (𝑐𝑜𝑠−1 −
4
5)
185. sin−1 (sinπ
6) 186. sin−1 (sin
5π
6)
187. cos−1 (cos2π
3) 188. cos−1 (cos −
2π
3)
𝟏𝟐
𝟏𝟑
𝟓√𝟔𝟏
𝟔𝟏
𝟑√𝟕
𝟕
−𝟕√𝟐𝟏𝟖
𝟐𝟏𝟖
√𝟖𝟓
𝟏𝟏
−𝟒
𝟑
𝝅
𝟒
𝒖𝒏𝒅𝒆𝒇𝒊𝒏𝒆𝒅
𝝅
𝟑
𝒖𝒏𝒅𝒆𝒇𝒊𝒏𝒆𝒅
𝟓
𝟏𝟑
𝟓√𝟕𝟒
𝟕𝟒
√𝟏𝟓
𝟏𝟓
−𝟓√𝟏𝟗𝟒
𝟏𝟗𝟒
𝟐√𝟏𝟎
𝟏𝟏
−𝟑
𝟒
𝝅
𝟔
𝒖𝒏𝒅𝒆𝒇𝒊𝒏𝒆𝒅
𝟐𝝅
𝟑
𝒖𝒏𝒅𝒆𝒇𝒊𝒏𝒆𝒅
Pre-Calc Trig ~21~ NJCTL.org
Trig Equations – Class Work
Find the value(s) of x such that 0 ≤ 𝑥 < 2𝜋, if they exist.
189. sin 𝑥 = 1 190. 3 tan2 𝑥 = 1
191. 𝑠𝑒𝑐2𝑥 − 2 = 0 192. 2𝑠𝑖𝑛2𝑥 + 3 = 7 sin 𝑥
193. 𝑐𝑠𝑐2𝑥 = 4 194. 3𝑠𝑒𝑐2𝑥 = 4
195. 𝑠𝑖𝑛2𝑥 − cos 𝑥 sin 𝑥 = 0 196. 2(sin 𝑥 + 1) = 𝑐𝑜𝑠2𝑥
197. sin 2𝑥 + cos 𝑥 = 0 198. sin𝑥
2+ cos 𝑥 = 0
199. cos 2𝑥 + cos 𝑥 = 2
𝒙 =𝝅
𝟐
𝒙 =𝝅
𝟔,
𝟓𝝅
𝟔,
𝟕𝝅
𝟔,
𝟏𝟏𝝅
𝟔
𝒙 =𝝅
𝟒,
𝟑𝝅
𝟒,
𝟓𝝅
𝟒,
𝟕𝝅
𝟒
𝒙 =𝝅
𝟔,
𝟓𝝅
𝟔
𝒙 =𝝅
𝟔,
𝟓𝝅
𝟔,
𝟕𝝅
𝟔,
𝟏𝟏𝝅
𝟔
𝒙 =𝝅
𝟔,
𝟓𝝅
𝟔,
𝟕𝝅
𝟔,
𝟏𝟏𝝅
𝟔
𝒙 = 𝟎, 𝝅,𝝅
𝟒,
𝟓𝝅
𝟒
𝒙 =𝟑𝝅
𝟐
𝒙 =𝝅
𝟐,
𝟑𝝅
𝟐,
𝟕𝝅
𝟔,
𝟏𝟏𝝅
𝟔
𝒙 = 𝝅,𝝅
𝟑,
𝟓𝝅
𝟑
𝒙 = 𝟎
Pre-Calc Trig ~22~ NJCTL.org
Trig Equations – Home Work
Find the value(s) of x such that 0 ≤ 𝑥 < 2𝜋, if they exist.
200. cos 𝑥 = −1 201. 2 sin2 𝑥 = 1
202. 𝑐𝑠𝑐2𝑥 − 2 = 0 203. 2𝑠𝑖𝑛2𝑥 − 3 = sin 𝑥
204. 𝑠𝑒𝑐2𝑥 = 4 205. 3𝑐𝑠𝑐2𝑥 = 4
206. 𝑐𝑜𝑠2𝑥 − cos 𝑥 sin 𝑥 = 0 207. (sin 𝑥 − 1) = −2𝑐𝑜𝑠2𝑥
208. sin 2𝑥 = 2tan 2𝑥 209. tan𝑥
2− sin 𝑥 = 0
210. sin 2𝑥 − sin 𝑥 = 0
𝒙 = 𝝅
𝒙 =𝝅
𝟒,
𝟑𝝅
𝟒,
𝟓𝝅
𝟒,
𝟕𝝅
𝟒
𝒙 =𝝅
𝟒,
𝟑𝝅
𝟒,
𝟓𝝅
𝟒,
𝟕𝝅
𝟒
𝒙 =𝟑𝝅
𝟐
𝒙 =𝝅
𝟑,
𝟐𝝅
𝟑,
𝟒𝝅
𝟑,
𝟓𝝅
𝟑
𝒙 =𝝅
𝟑,
𝟐𝝅
𝟑,
𝟒𝝅
𝟑,
𝟓𝝅
𝟑
𝒙 =𝝅
𝟐,
𝟑𝝅
𝟐,
𝝅
𝟒,
𝟓𝝅
𝟒
𝒙 =𝟕𝝅
𝟔,
𝟏𝟏𝝅
𝟔,
𝝅
𝟐
𝒙 = 𝟎, 𝝅,𝝅
𝟐,
𝟑𝝅
𝟐
𝒙 = 𝟎, 𝝅,𝝅
𝟐,
𝟑𝝅
𝟐
𝒙 = 𝟎, 𝝅,𝝅
𝟑,
𝟓𝝅
𝟑
Pre-Calc Trig ~23~ NJCTL.org
Trigonometry Unit Review
Multiple Choice
1. Given the terminal point of (√2
2,
−√2
2) find tan 𝜃.
a. π
4
b. −π
4
c. -1
d. 1
2. Knowing sec 𝑥 =−5
4 and the terminal point is in the second quadrant find cot 𝜃.
a. −4
5
b. 3
5
c. −4
3
d. −3
4
3. What is the phase shift of 𝑦 =5
3cos(6𝑥 − 2𝜋) + 3?
a. 1
2π
b. π
3
c. 1
3
d. 2𝜋
4. The difference between the maximum of 𝑦 = 2 cos (2 (𝑥 +𝜋
3)) + 1 and 𝑦 = −3 cos(4𝑥 − 𝜋) − 2 is
a. 1
b. 2
c. 3
d. 8
5. Given ∆𝐴𝐵𝐶, 𝑤𝑖𝑡ℎ 𝐴 = 35°, 𝑎 = 5, & 𝑐 = 7, 𝑓𝑖𝑛𝑑 𝐵.
a. 18.418
b. 53.418
c. 91.582
d. both a and b
6. Given ∆𝐴𝐵𝐶, 𝑤𝑖𝑡ℎ 𝐴 = 50°, 𝑎 = 6, & 𝑐 = 8, 𝑓𝑖𝑛𝑑 𝐵.
a. 1.021
b. 40
c. 128.979
d. no solution
7. Given ∆𝐴𝐵𝐶, 𝑤𝑖𝑡ℎ 𝐴 = 50°, 𝑏 = 6, & 𝑐 = 8, 𝑓𝑖𝑛𝑑 𝐵.
a. 6.188
b. 32.456
c. 47.967
d. 82.033
8. (sec 𝑥 + tan 𝑥)(sec 𝑥 − tan 𝑥) =
a. 1 + 2 sec 𝑥 tan 𝑥
b. 1 − sec 𝑥 tan 𝑥
c. 1 −2 sin 𝑥
𝑐𝑜𝑠2𝑥
d. 1
C
C
B
A
C
D
C
D
Pre-Calc Trig ~24~ NJCTL.org
9. Find the exact value of sin𝜋
12
a. √6−√2
4
b. √6+√2
4
c. √6−√2
2
d. √6−√2
2
10. On the interval [0, 2π), sin 2𝑥 = 0, thus x =
a. 0
b. π
2
c. 3π
2
d. all of the above
11. Find the exact value of cos 105
a. √2−√3
2
b. −√2−√3
2
c. √2+√3
2
d. −√2+√3
2
12. 𝑠𝑖𝑛4𝑥 =
a. 1
8(3 − cos 𝑥 + cos 4𝑥)
b. 1
8(3 + cos 𝑥 + cos 4𝑥)
c. 1
8(3 + 4 cos 𝑥 + cos 4𝑥)
d. 1
8(3 − 4cos 𝑥 + cos 4𝑥)
13. Rewrite cos 6𝑥 sin 4𝑥 as a sum or difference.
a. 1
2cos 10x −
1
2cos2x
b. 1
2cos 10x +
1
2cos2x
c. 1
2sin 10x − sin2x
d. 1
2sin 10x −
1
2sin2x
14. On the interval [0, 2π), sin 5𝑥 + sin 3𝑥 = 0
a. π
4
b. kπ
4, where k ∈ Integers
c. kπ
4, where k ∈ {0,1,2,6}
d. no solution on the interval given
15. 𝑠𝑖𝑛−1 (sin4𝜋
3) =
a. 4𝜋
3
b. −𝜋
3
c. 𝑏𝑜𝑡ℎ 𝑎 𝑎𝑛𝑑 𝑏
d. Undefined
A
D
B
D
D
C
B
Pre-Calc Trig ~25~ NJCTL.org
16. On the interval [0, 2π), solve 2sin2 𝑥 + 3 cos 𝑥 = 3
I. 0 II. π
3 III.
5π
3
a. I only
b. II and III
c. I and III
d. I, II, and III
Extended Response
1. The range of a projectile launched at initial velocity 𝑣0 and angle 𝜃, is
𝑟 =1
16𝑣0
2 sin 𝜃 cos 𝜃,
where r is the horizontal distance, in feet, the projectile will travel.
a. Rewrite the formula using double angle formula.
b. A golf ball is hit 200 yards, if the initial velocity 200 ft/sec, what was the angle it was hit?
c. If the golfer struck the ball at 45°, how far would the ball traveled?
2. A state park hires a surveyor to map out the park.
a. A and B are on opposite sides of the lake, if the surveyor stands at point C and measures
angle ACB= 50 and CA= 400’ and CB= 350’, how wide is the lake?
b. At a river the surveyor picks two spots, X and Y, on the same bank of the river and a tree, C,
on opposite bank. Angle X= 60 and angle Y= 50 and XY=300’, how wide is the river?
(Remember distance is measured along perpendiculars.)
c. The surveyor measured the angle to the top of a hill at the center of the park to be 32°. She
moved 200’ closer and the angle to the top of the hill was 43°. How tall was the hill?
D
𝒓 =𝟏
𝟑𝟐𝒗𝟎
𝟐 𝐬𝐢𝐧 𝟐𝜽
𝜽 = 𝟏𝟒. 𝟑𝟒𝒐
𝒓 = 𝟏𝟐𝟓𝟎 𝒇𝒆𝒆𝒕
𝟑𝟐𝟎. 𝟐 𝒇𝒆𝒆𝒕
𝟐𝟏𝟏. 𝟖 𝒇𝒆𝒆𝒕
𝟑𝟕𝟖. 𝟖 𝒇𝒆𝒆𝒕
Pre-Calc Trig ~26~ NJCTL.org
3. The average daily production, M (in hundreds of gallons), on a dairy farm is modeled by
𝑀 = 19.6 sin (2𝜋𝑑
365+ 12.6) + 45
where d is the day, d=1 is January first.
a. What is the period of the function?
b. What is the average daily production for the year?
c. Using the graph of M(d), what months during the year is production over 5500 gallons a day?
4. A student was asked to solve the following equation over the interval [0, 2𝜋). During his calculations
he might have made an error. Identify the error and correct his work so that he gets the right
answer.
cos 𝑥 + 1 = sin 𝑥
cos2x + 2 cos x + 1 = 𝑠𝑖𝑛2𝑥
cos2x + 2 cos x + 1 = 1 − 𝑐𝑜𝑠2𝑥
2 cos 𝑥 = 0
cos 𝑥 = 0
π
2,3π
2
𝟑𝟔𝟓
𝟒𝟓𝟔𝟔 𝒈𝒂𝒍𝒍𝒐𝒏𝒔
February thru May
Error is on line 4
Line 4 should read
𝟐 𝐜𝐨𝐬𝟐 𝒙 + 𝟐 𝐜𝐨𝐬 𝒙 = 𝟎
The rest of the problem is
𝟐 𝐜𝐨𝐬 𝒙 (𝐜𝐨𝐬 𝒙 + 𝟏) = 𝟎
𝟐 𝐜𝐨𝐬 𝒙 = 𝟎 𝐜𝐨𝐬 𝒙 + 𝟏 = 𝟎
𝐜𝐨𝐬 𝒙 = 𝟎 𝐜𝐨𝐬 𝒙 = −𝟏
𝒙 =𝝅
𝟐, 𝝅,
𝟑𝝅
𝟐