We know that sin(2⋅x)=2⋅sin(x)⋅cos(x)and cos(2x)=cos^2(x)−sin^2(x). Use the appropriate formula to expand cos(8x) in terms of one of these two formulas.
The Attempt at a Solution
I am not looking for help with the solution, I just want to know what the question is asking me to do. Is it asking me to sub cos(8x) into these equations like cos(8x) = cos^2(4x) - sin^2(4x)? If not what is it asking me to do?