1. jika cos (1 1/2x)=1/3 maka sin 3x? Tolong jawab...

jawab
trigonometri

cos (3/2 x)  = 1/3
sin (3/2 x) = √( 1- cos² (3/2x)) = √( 1- 1/9) = √(8/9) = 2/3 √2

sin (3x)= 2 sin (3/2 x ) cos (3/2 x)
sin (3x) = 2(2/3 √2). (1/3)
sin (3x) = 2(2/3)(1/3) √2
sin (3x) = 4/9  √2