sin (4x) = 0
4x = πn n ∈ Z
x = πn/4 n∈ Z
корни в интервале [0, 2π]
0 <= πn/4 <= 2π
0 <= n <= 8
и Ищем корни от 0 до 8 (х = πn/4)
0
π/4
2π/4 = π/2
3π/4
4π/4 = π
5π/4
6π/4 = 3π/2
7π/4
8π/4 = 2π
