Question

sin660° + sin 780°





tell answer with detailed explanation. ​

Answer 1

Answer:

sin 780° = sin 60° = √3/2

sin 660° = 300° = -√3/2

sin 420° = 60° = √3/2

sin 780 - sin 660 - sin 420 + sin 60

= √3/2 - (-√3/2) - √3/2 +√3/2

= 0