а) 4sin(x) = -4
sin(x) = -1
x = -π/2 + 2πk ; k € Z
б) 2cos^2 (x) - 3cos(x) - 2 = 0
cos(x) = -1/2 cos(x) = 2
x = 2π/3 + 2πk нет решений
x = -2π/3 + 2πk
ответ : 2π/3 + 2πk , -2π/3 + 2πk ; k € Z
