Решить уравнение: cos (x-p/4) = -1/2
Cos(x - π/4) = -1/2 x - π/4 = ±2π/3 + 2πn, n ∈ Z x = ±2π/3 + π/4 + 2πn, n ∈ Z Ответ: x = ±2π/3 + π/4 + 2πn, n ∈ Z. P.s.: arccos(-x) = π - arccosx