Рішення
cos(3x+п/4)=-1/2

Ответ:

Пошаговое объяснение:

cos(3x + π/4) = - 1/2;  3x + π/4 = ± (π - arccos1/2) + 2πn, n ∈ Z;  3x = - π/4 ± (π - π/3) +2πn, n ∈ Z;   3x = - π/4 ± 2π/3 + 2πn, n ∈ Z, a) 3x₁ = - π/4 - 2π/3 + 2πn,       n ∈ Z,  3x₁ = - 11π/12 + 2πn, n ∈ Z;  x₁ = - 11π/36 + 2π/3 n, n ∈ Z;  b) 3x₂ = - π/4 + 2π/3 + 2πn, n ∈ Z, 3x₂ = 5π/12 + 2πn,  n ∈ Z,  x₂ = 5π/36 + 2π/3n,  n ∈ Z         Ответ:   x₁ = - 11π/36 + 2π/3 n, n ∈ Z;   x₂ = 5π/36 + 2π/3n,  n ∈ Z