Jika cos x = 3/5 dengan x sudut lancip, maka nilai sin 3x - sin x = ...

cos x = 3/5
sin x = 4/5
sin 2x = 2.sin x. cos x
= 2.(4/5).(3/5)
= 24/25
cos 2x = (cos x) ^2 - (sin x) ^2
= (3/5)^2 - (4/5)^2
= 9/25 - 16/25
= -7/25
sin 3x = sin (2x + x)
= sin 2x. cos x + cos 2x.sin x
= (24/25).(3/5) + (-7/25).(4/5)
= 72/125 - 28/125
= 44/125