Tentukan nilai dari sin 555⁰
1/4 (√2 – √6)
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= sin 555°
= sin (360° + 195°)
= sin 195°
= sin (180° + 15°)
= – sin 15°
= – (sin 45° cos 30° – sin 30° cos 45°)
= – (1/2 √2 (1/2 √3) – 1/2 ( 1/2 √2 ))
= – (1/4 √6 – 1/4 √2))
= – 1/4 √6 + 1/4 √2
= 1/4 (-√6 + √2)
= 1/4 (√2 – √6)