Chapter 4 Trigonometric Functions
Chapter 4 Trigonometric Functions
Chapter 4 Trigonometric Functions
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<strong>Trigonometric</strong> <strong>Functions</strong><br />
46. − 250°+ 360°= 110°<br />
Because the angle is in quadrant II, the reference<br />
angle is θ′ = 180°− 110°= 70°.<br />
47. − 335°+ 360°= 25°<br />
Because the angle is in quadrant I, the reference<br />
angle is θ′ = 25°.<br />
48. − 359°+ 360°= 1°<br />
Because the angle is in quadrant I, the reference<br />
angle is θ′ = 1°.<br />
57.<br />
58.<br />
11 11 16 5<br />
− π + 4π<br />
= − π + π =<br />
π<br />
4 4 4 4<br />
Because the angle is in quadrant III, the reference<br />
5π<br />
π<br />
angle is θ′ = − π = .<br />
4 4<br />
17 17 24 7<br />
− π + 4π<br />
=− π + π =<br />
π<br />
6 6 6 6<br />
Because the angle is in quadrant III, the reference<br />
7π<br />
π<br />
angle is θ′ = − π = .<br />
6 6<br />
49. Because 4.7 lies between π ≈ 3.14 and 3 π ≈ 4.71 , it<br />
2<br />
is in quadrant III. The reference angle is<br />
θ′ = 4.7 −π<br />
≈ 1.56 .<br />
50. Because 5.5 lies between 3 π ≈ 4.71 and 2π ≈ 6.28 ,<br />
2<br />
it is in quadrant IV. The reference angle is<br />
θ′ = 2π<br />
−5.5 ≈ 0.78 .<br />
51. 565°− 360°= 205°<br />
Because the angle is in quadrant III, the reference<br />
angle is θ ′ = 205°− 180°= 25°.<br />
52. 553°− 360°= 193°<br />
Because the angle is in quadrant III, the reference<br />
angle is θ′ = 193°− 180°= 13°.<br />
53.<br />
54.<br />
55.<br />
56.<br />
17 π 17 12 5<br />
− 2π<br />
= π − π =<br />
π<br />
6 6 6 6<br />
Because the angle is in quadrant II, the reference<br />
5π<br />
π<br />
angle is θ′ = π − = .<br />
6 6<br />
11 π 11 8 3<br />
− 2π<br />
= π − π =<br />
π<br />
4 4 4 4<br />
Because the angle is in quadrant II, the reference<br />
3π<br />
π<br />
angle is θ′ = π − = .<br />
4 4<br />
23 π 23 16 7<br />
− 4π<br />
= π − π =<br />
π<br />
4 4 4 4<br />
Because the angle is in quadrant IV, the reference<br />
7π<br />
π<br />
angle is θ′ = 2π<br />
− = .<br />
4 4<br />
17 π 17 12 5<br />
− 4π<br />
= π − π =<br />
π<br />
3 3 3 3<br />
Because the angle is in quadrant IV, the reference<br />
5π<br />
π<br />
angle is θ′ = 2π<br />
− = .<br />
3 3<br />
59.<br />
60.<br />
25 25 36 11<br />
− π + 6π<br />
=− π + π =<br />
π<br />
6 6 6 6<br />
Because the angle is in quadrant IV, the reference<br />
11π<br />
π<br />
angle is θ′ = 2π<br />
− = .<br />
6 6<br />
13 13 18 5<br />
− π + 6π<br />
= − π + π =<br />
π<br />
3 3 3 3<br />
Because the angle is in quadrant IV, the reference<br />
5π<br />
π<br />
angle is θ′ = 2π<br />
− = .<br />
3 3<br />
61. 225° lies in quadrant III. The reference angle is<br />
θ ′ = 225°− 180°= 45°.<br />
2<br />
cos 45°=<br />
2<br />
Because the cosine is negative in quadrant III,<br />
2<br />
cos 225 ° = − cos 45 ° = − .<br />
2<br />
62. 300° lies in quadrant IV. The reference angle is<br />
θ ′ = 360°− 300°= 60°<br />
.<br />
3<br />
sin 60°=<br />
2<br />
Because the sine is negative in quadrant IV,<br />
3<br />
sin 300°=− sin 60°=− .<br />
2<br />
63. 210° lies in quadrant III. The reference angle is<br />
210 180 30<br />
θ ′ = °− °= °.<br />
3<br />
tan 30°=<br />
3<br />
Because the tangent is positive in quadrant III,<br />
3<br />
tan 210 ° = tan 30°= .<br />
3<br />
526<br />
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