Помогите плиз с алгеброй!1! cos(3x-п/4)=1/2
Cos(3x - π/4) = 1/2 3x - π/4 = π/3 + 2πn 3x - π/4 = -π/3 + 2πn 3x = π/3 + 2πn + π/4 3x = -π/3 + 2πn + π/4 3x = 7π/12 + 2πn 3x = -π/12 + 2πn x = 7π/36 + 2/3 * πn x = -π/36 + 2/3 * πn Ответ: -π/36 + 2πn/3; 7π/36 + 2πn; n ∈ Z