did you even look up your half-angle formula? It says that
cos(θ/2) = √[(1+cosθ)/2]
I think the substitution is now clear.
Use the half-angle formula to simplify the given expression.
squareroot 1+cos12x/2
3 answers
is it cos12x?
No.
You are half right. θ=12x is the right substitution to use, but if θ = 12x, what you have is cos(θ/2) = cos 6x
You are half right. θ=12x is the right substitution to use, but if θ = 12x, what you have is cos(θ/2) = cos 6x