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Nilai funghsi trigonometri
sin120  = sin (180-60) =sin 60 = 1/2 √3
sin 150 = sin(180-30) = sin 30 = 1/2
cos 330 = cos (360 - 30) = cos 30= 1/2√3
cos 240 = cos (180+60) =- cos 60 = - 1/2

(sin 120 + sin 150) / (cos 330 + cos 240)=
= ( 1/2 √3 + 1/2)/ (1/2 √3 - 1/2) kalikan 2/2
= (√3 + 1)/(√3 -1) ...kalikan (√3 -1)/(√3-1)
= (3 - 1)/ (2 + 2√3)
= 2/(2 + 2√3)
 = 1/(1 + √3) ...kalikan (1 - √3)/(1 -√3)
= (1 - √3)/(1 -3)
= (1 - √3)/ (-2)
= - 1/2  + 1/2√3