cos2x - cosx = 0
Distribute the cos2x term: cos^2(x) - cosx = 0
Use the identity cos^2(x) = 1 - sin^2(x): 1 - sin^2(x) - cosx = 0
Rearrange the terms: sin^2(x) + cosx - 1 = 0
Since sin^2(x) + cos^2(x) = 1, we can rewrite sin^2(x) as 1 - cos^2(x): 1 - cos^2(x) + cosx - 1 = 0
Simplify: -cos^2(x) + cosx = 0
Factor out a negative sign: cosx(cosx - 1) = 0
Set each factor to zero: cosx = 0 or cosx - 1 = 0
Solve for x: Case 1: cosx = 0 x = π/2 + πn, где n - целое число
Case 2: cosx - 1 = 0 cosx = 1 x = 2πn, где n - целое число
Ответ: x = π/2 + πn, x = 2πn
