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C H A P T E R 5 Analytic Trigonometry

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484 Chapter 5 <strong>Analytic</strong> <strong>Trigonometry</strong><br />

72.<br />

73.<br />

tan x tan <br />

2sin x cos cos x sin 0<br />

1 tan x tan <br />

tan x 0<br />

2sin x1 cos x0 0<br />

1 tan x0<br />

cos x cos <br />

4<br />

Graphically: Graph<br />

tanx 2 sinx 0<br />

The points of intersection occur at x <br />

4<br />

tan x<br />

2 sin x 0<br />

1<br />

sin x<br />

2 sin x<br />

cos x<br />

sin x1 2 cos x 0<br />

sin x 2 sin x cos x<br />

sin x 0 or cos x 1<br />

2<br />

<br />

<br />

<strong>Analytic</strong>ally: cosx 4 cosx 1 4<br />

sin x sin <br />

4<br />

cos x cos <br />

4<br />

<br />

74. tanx cosx 0<br />

2<br />

Answers: 0, 0, 3.14, 0 ⇒ x 0, <br />

x 0, x 5<br />

,<br />

3 3<br />

<br />

sin x sin 1<br />

4<br />

2 cos x 2<br />

2 1<br />

2 cos x 1<br />

<br />

<br />

y1 cosx 4 cosx 4 and y2 1.<br />

and x 7<br />

4 .<br />

4<br />

cos x 1<br />

2<br />

cos x 2<br />

2<br />

x 7<br />

,<br />

4 4<br />

0 2<br />

−4<br />

0<br />

2<br />

−2<br />

2

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