Problem
Expand the expression \(\cos(3x)\) using the triple-angle formula.
Solution
Step 1 ：We know that the triple-angle formula for cosine is \(\cos(3x) = 4\cos^3(x) - 3\cos(x)\).
Step 2 ：Therefore, the expansion of \(\cos(3x)\) will be \(4\cos^3(x) - 3\cos(x)\).
