Question

Sin150 cos120 + cos330 sin660 = -1

Answer 1

Answer:

Step-by-step explanation:

sin(90+60)cos(90+30)+cos(360-30)sin(270+390)

cos(60)(-sin(30))+cos(30)(-cos(390))

(1/2)(-1/2)+root3/2(-cos360+30)

-1/4+root3/2*(root3/2)

-1/4+(-3/4)

-4/4

-1