How do you find the exact value of this trig function without a calculator?

Question

(1-(2(cos^2))(43.5°))/((sin84° sin7°)−(sin6° sin277°))

Answer 1

I think there is a slight bit of mis-parenthesizing here, in relation to "cos 2"--it's not clear to me whether you meant the square of a cosine, or the cosine of a double angle.

 

I do not see any way to get an exact value.