Cos(3x-87)=1/2 найдите x
3x -87 = +-arcCos1/2 + 2πk , k ∈ Z 3x - 87 = +-π/3 + 2πk , k ∈ Z 3x = 87 +- π/3 + 2πk , k ∈Z x = 29 +-π/9 + 2πk/3 , k ∈ Z