nilai dari cos 75 - cos 15 adalah......
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Pertanyaan
nilai dari cos 75 - cos 15 adalah......
1 Jawaban
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1. Jawaban arafdinaovzlyj
cos 75 - cos 15
= cos(45 + 30) - cos(60 - 45)
= (cos 45 . cos 30 - sin 45 . sin 30) - (cos 60 . cos 45 + sin 60 . sin 45)
= ((1/2√2) . (1/2√3) - (1/2√2) . (1/2)) - ((1/2) . (1/2√2) + (1/2√3) . (1/2√2))
= 1/4√6 - 1/4√2 - ( 1/4√2 + 1/4√6)
= 1/4√6 - 1/4√2 - 1/4√2 - 1/4√6
= - 2/4√2
= - 1/2√2