Question

tan(-150°)cos(-570°)cos(-1140°)/cot(-240°)sin（-690°)

Answer 1

tan(-150°)cos(-570°)cos(-1140°)/cot(-240°)sin（-690°)

= tan(-150°)cos(150°)cos(-60°)/cot(120°)sin（30°)

= -tan(30°)cos(30°)cos(60°)/-cot(60°)sin（30°)

= sin(30°)cos(30°)cos(60°)sin(60°)/cos(30°)cos(60°)sin（30°)

= sin(60°)

= 根号3 / 2.