hitunglah nilai dari cos 2/3π - cos 5/3π + sin 3/4

Trigonometri.

cos (2/3 π) - cos (5/3 π) + sin (3/4 π)
= cos 120° - cos 300° + sin 135°
= -1/2 - 1/2 + 1/2 √2
= 1/2 (√2 - 2)