ttg trigonom. tolong yaa makasih.

4 cos a = 2
3/2π < a < 2π
3/2(180) < a < 2(180)
270 < a < 360
a berada di kuadran 4
4cos a = 2
cos a = 2/4 = 1/2
a = (360-60) = 300
sin a = sin 300
= sin (360-60)
= -sin 60
= -√3/2