Question

How to solve this identity? Thank you!

`4(sin²a-3/4)=4sin(a+60°)*sin(a-60°)`

Answer 1

`RHS=4sin(a+60°)*sin(a-60°)`

`=4(sin^2a-sin^2 60°)`

`=4(sin^2a-(sqrt3/2)^2)`

`=4(sin²a-3/4)=LHS`