Question

Prove that sin150o cos 120o +cos 330 i sin 660 o = 1

Answer 1

Answer:

Step-by-step explanation:

Sin150° cos 120° +cos 330°sin 660°

=> sin(180-30) * Cos(180 - 60) + Cos (360 - 30) * Sin (2*360 - 60)

=> (Sin30°)  *  (-Cos60°) +  (Cos30°)  *  (-Sin60°)

=> 1 /2* (-1/2)  + (√3/2)  ( - √3/2)

=> - 1/4 + (-3/4)

=> -4/4 = - 1.