Solve 2 cos 2𝑥° = 1 for 0 ≤ 𝑥 ≤ 180.
2cos(2x)=1|:2cos(2x)=12|±arccos()2x=±arccos(12)+360⋅kk∈Z2x=±60∘+360∘⋅k|:2x=±30∘+180∘⋅kx1=30∘x2=−30∘+180∘x2=150∘