10 класс алгебра
помогите пожалуйста 2 и 3 задания!!!!

2) а) Sin(3x -2π/3) ≥1/2

   π/6 + 2πn  ≤ 3x -2π/3 ≤5π/6 + 2πn , n ∈Z

   π/6 + 2πn +2π/3   ≤ 3x  ≤5π/6 + 2πn+2π/3  , n ∈Z

   π/18 + 2πn/3 +2π/9   ≤ x  ≤5π/18 + 2πn/3+2π/9  , n ∈Z  

б)Cos(2x +3π/4) ≤ -√2/2

  3π/4 + 2πk ≤2x +3π/4 ≤5π/4 + 2πk , k ∈Z

 3π/4 + 2πk ≤2x +3π/4 ≤5π/4 + 2πk , k ∈Z

 3π/4 + 2πk ≤2x +3π/4 ≤5π/4 + 2πk , k ∈Z

 3π/4 + 2πk ≤2x +3π/4 ≤5π/4 + 2πk , k ∈Z

 3π/4 + 2πk - 3π/4  ≤ 2x ≤5π/4 + 2πk - 3π/4, k ∈Z

 2πk ≤ 2x ≤ 2π/4 + 2πk, k ∈Z

 πk ≤ x ≤ π/4 + πk, k ∈Z

3)4(1 - Sin²x) -(2√2 -2)Sinx > 4 - √2

   4 - 4Sin²x -(2√2 -2)Sinx > 4 - √2

   4Sin²x + (2√2 -2)Sinx - √2 < 0

Sinx = (-√2+1 +-√(2 -2√2 +1 +4√2) )/4 = (-√2 +1 +-√(√2+1)²)/4 = -√2 +1 +-(√2 +1) )/4

a) Sinx = 1/2                     б) Sinx = -√2/2

-√2/2 < Sinx < 1/2

-π/4 + 2πk < x < π/6 + 2πk , k ∈ Z