nilai dari sin150 +sin 120 per cos 300-cos 210

[sin (180-30) + sin (180-60)] / [cos (180+30) - cos (360-60)]
= (sin 30 + sin 60) / (-cos 30 - cos 60)
= (1/2 + 1/2 akar 3) / (-1/2 akar 3 - 1/2)
= -1

[sin (180-30) + sin (180-60)] / [cos (360-60) - cos (180+30)]
= (sin 30 + sin 60) / (cos 60 - (- cos30))
= (½+½√3) / (½ - (-½√3)
= 1