Page 34 - modul trigonometri bilingual

Other ways:

tan 240° − cos 570° = tan(270° − 60°) − cos (360° + 120°)

= cot 30° − cos 120 °
3
= − cos(270° − 60°)
√3

√3×√3
= − (−sin 60°)
√3

√3×√3
= + sin 60°
√3
1
= √3 + √3
2
3
= √3
2
1
So, the value tan 240° − cos 570° be √3
2
Example 2.3

Specify the simplest form of the following trigonometric form.

1. 10 tan(180° + ) sin(270° − ) − 3 cos(90° + )
2. cot(360° − ) − 3 csc(270° − ) − sec(− )

Alternative Solutions

1. 10 tan(180° + ) sin(270° − ) − 3 cos(90° + )
= 10 tan (− cos ) − 3 (− sin )
sin
= −10 × × cos + 3 sin
cos
= −10 sin + 3 sin

= −7 sin
So, the simplest form of 10 tan(180° + ) sin(270° − ) −
3 cos(90° + ) is −7 sin
2. cot(360° − ) − 3 csc(270° − ) − sec(− )

= − cot − 3(− sec ) − sec
= − cot + 3 sec − sec
= − cot + 2 sec
3. So, the simplest form of cot(360° − ) − 3 csc(270° − ) −

sec(− ) is − cot + 2 sec

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