Nilai dari sin 280-sin 20/cos340-cos 80

jawab

(sin 280 - sin 20)/cos 340 - cos 80 =

= ( 2cos 1/2(280+20) sin 1/2(280-20))/ (- 2 sin 1/2(280+20) sin1/2(280-20)

= (2 cos 300.sin130) /(-2 sin 150 sin 130)

= cos 300/ - sin 150

= cos (360-60) / - sin(180-30)

= cos 60 / - sin 30

=  (1/2) /  -(1/2)

=  -1