Dik: tan a=1/2 dan tan b=1/3. dit nilai dari tan (a – 2b)
tan 2b
= (2 . tan b) / (1 – tan² b)
= (2 . 1/3) / (1 – (1/3)²)
= (2/3) / (9/9 – 1/9)
= (2/3) / (8/9)
= 2/3 . 9/8
= 2/8 . 9/3
= 1/4 . 3
= 3/4
………………………………….
tan (a – 2b)
= (tan a – tan 2b) / (1 + tan a . tan 2b)
= (1/2 – 3/4) / (1 + 1/2 . 3/4)
= (2/4 – 3/4) / (1 + 3/8)
= (-1/4) / (11/8)
= -1/4 . 8/11
= -8/4 . 1/11
= -2/11
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Kelas 10
Pelajaran Matematika
Bab 6 Trigonometri Dasar
Kata kunci : –
Kode kategorisasi : 10.2.6