Question

sin78-sin66-sin42+sin6 =
?

Answer 1

-1/2 is the answer

Hope it helps

Answer 2

Answer:

-1/2

Step-by-step explanation:

Firstly make pairs,

Sin78+Sin6-(Sin66+Sin42)

2Sin42.Cos36-2Sin54.Cos12

2Sin42.Cos36-2Cos36.Sin78

2Cos36.(Sin42-Sin78)

2Cos36.(2Sin(-18)).Cos60

-4Cos36.Sin18.Cos60

-4*$\sqrt{5}$+1/4*$\sqrt{5}$-1/4*1/2

-4/8

-1/2