Matematika

Pertanyaan

Tolong pake cara juga, please jng asal2lan
Tolong pake cara juga, please jng asal2lan

1 Jawaban

  • 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))