C H A P T E R 5 Analytic Trigonometry

77. sin 4x 2 sin 2x cos 2x 78.
22 sin x cos xcos 2 x sin 2 x
4 sin x cos x2 cos 2 x 1
8 cos 3 x sin x 4 cos x sin x
−2 2
2
−2
79. tan2 2x sin2 2x
cos2 2x
1 cos 4x
2 1 cos 4x
1 cos 4x 1 cos 4x
2
81.
83.
sin 2 x tan 2 x sin 2 x sin2 x
cos 2 x sin4 x
cos 2 x
cos 2x
1 2
1 cos 2x
2
1 cos 4x
1 2 cos 2x
2
21 cos 2x
2
2 4 cos 2x 1 cos 4x
41 cos 2x
3 4 cos 2x cos 4x
41 cos 2x
2 3
1 2 cos 2x cos 2 2x
4
1 cos 2x
2
−2 2
4
−1
Review Exercises for Chapter 5 519
1 cos 2x
1 cos 2x 1 1 2 sin2 x
1 2 cos x2 1
80. cos 2 3x
1 3
1 cos 150
2
sin75
2 3
2
2
2
1
2 3
2
1 3
1 cos 150
2
cos75
2
2
1
2 3
2
1 cos 150
tan75 sin 150 1 3
2
2 3
1
2
2 3
2
2 sin2 x
2 cos 2 x
tan 2 x
1 cos 6x
2
82. cos 2 x tan 2 x sin 2 x
1 cos 2x
2