Question

Tolong jawabannya yaa. Nomor 6. Pake cara yaa. Terima kasih sebelumnya..

Answer 1

Verified answer

TRIGonomeTRI

5/12 π = 5/12 × 180° = 75°
1/12 π = 15°

cos 75° - cos 15°
= -2 sin (75° + 15°)/2 sin (75° - 15°)/2
= -2 sin 45° sin 30°
= -2 . 1/2 √2 . 1/2
= -1/2 √2

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cos a - cos b = -2 sin (a+b)/2 sin (a-b)/2