Tolong pake cara juga, please jng asal2lan
Matematika
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Pertanyaan
Tolong pake cara juga, please jng asal2lan
1 Jawaban
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1. Jawaban dillaalf
Pada kuadran III
sin x = depan/miring = -a
Anggap:
Sisi depan = a
Sisi miring = 1
Maka sisi samping = akar (1 - a^2)
Jadi,
cos x = - (akar (1 - a^2)) karena di kuardan III
sin 2x = 2 sin x cos x
= 2 × (-a) × (- akar (1 - a^2))
= 2a(akar (1 - a^2))
cos 2x = (cos x)^2 + (sin x)^2
= (- akar (1 - a^2))^2 + (- a)^2
= (1 - a^2) + a^2
= 1
Jadi,
sin 2x cos 2x = 2a(akar (1 - a^2)) × 1
= 2a(akar (1 - a^2))