Please bantu ya teman

nilai fungsi trigoometri

a.
cos 240 = cos(180+60) = -cos 60 = -¹/₂
sin 240 = sin (180 +60) = - sin 60 = ¹/₂ √3
cos 240 + 1/√3 sin 240 = - ¹/₂ + 1/√3 (¹/₂ √3)=  - ¹/₂ + ¹/₂ = 0

b.
sin 330 = sin (360-30) = - sin 30 = - ¹/₂
tan (-240) = - tan 240 = - tan(180+60) = - tan 60 = -√3
cos 210 = cos (180+30) = -cos 30 = - ¹/₂ √3
cot (315) = cos(360-45) = - cos 45 = - 1

sin (330).tan(-210) - cos (210). cot (315) =
= (-¹/₂)(-√3) - (¹/₂ √3)(-1)
= ¹/₂√3 + ¹/₂ √3
= √3

c.
sin 270 = -1
cos 135 = cos (180-45) = - cos 45 = - 1/2 √2
tan 135 = tan(180-45)  = - tan 45 = - 1
sin 150 = sin(180-30) = sin 30 = 1/2
cos 225= cos (180+45) = 1/2 √2

[ sin 270. cos 135. tan 135)] / [sin 150 . cos 225=
= (-1)(-1/2 √2)(-1)  / (1/2)(1/2 √2)
= (-1)(-1) / (1/2)
= 1/(1/2)
= 2