I was to simplify an expression, I came to this:
But, I couldn't simplify it further.
I checked the answer and it was $\sin10^\circ$. But I can't understand why.
Can anyone help?
EDIT: $\theta$ was $10^\circ$. I myself generalized it.
The two sides are not equivalent. So $10^\circ$ seems to have a special characteristic which we should use here.