jika Cosec α = 3, sudut α terletak di kuadran II,maka nilai Cos α adalah..........

Mapel : Matematika
Kelas : X SMA
Bab : Trigonometri

Pembahasan :
Cosec α = 3
1/Sin α = 3
Sin α = 1/3

Depan = 1
Miring = 3
Samping = - 2√2 (Dalil Pythagoras)

Cos α = Samping/Miring
Cos α = - (2√2)/3