Объяснение:
cos120°=cos(90°+30°)=-sin30°=-1/2
sin135°=sin(90°+45°)=cos45°=√2/2
tg150°=tg(90°+60°)=-ctg60°=-1/√3
1) cos120°sin135°tg150°=(-1/2)×(√2/2)×*-1/√3)=√2/(4√3)=1/(2√6)
tg125°=tg(180°-55°)=-tg55°
2) tg125°/ tg55°=-tg55°/tg55°=-1
