(1)sin π 4 cos 19π 6 tan 21π 4 = 2 2 cos(π+ π 6 )tan π 4 = 2 2 ×(- 3 2 )×1=- 6 4 .(2) 3 sin(-1200°)tan 19π 6 -cos585°tan(- 37π 4 ).=