• Cos a =3/5
    Sin(a+β) = 4/5.-1/2√3 + 1/2.3/5
    =-4√3/10 + 3/10
    = -4√3+3/10

    Cos(90+A+B) = -sin (A+B )
    =4√3-3/10

    Semoga membantu

Pertanyaan Lainnya