Sin 90° (cos 135° tg 150°-cos 135° tg 120°)²= 1 (-√2/2*(-√3/3)-√2/2*√3)²=(-6√6-2√6)²=(-8√6)²=64*6=384
cos 135°= cos (90°+45°)= -sin45°= -√2/2
tg 150=tg (180°-30°)=-tg30°= -√3/3
tg 120°=tg (180°-60°)=-tg60°= -√3
