2cosx+sqrt3=0 sin(2P-x)-cos(3P/2+x)+1=0 sin9P/4 cos(-4P/3)

1) 2 * cos(x) = -√3

  cos(x) = -√3/2

 x = arccos(- √3/2) +- 2 * π *n, где n - натуральное число

x = 2π / 3 +- 2 * π *n

2) Так как sin(2 * π - x) = -sin(x), cos(3* π / 2 + x) = sin(x), получим уравнение:

- sin(x) - sin(x) + 1 = 0

sin(x) = 1

 x = arxsin(1) +- 2 * π * n

x =  π/2 +- 2 * π * n.

3) sin(9 * π / 4) = sin(2 * π + π/4) = sin(π/4) = √2/2;

    cos(- 4 * π / 3) = cos (- π - π/3) = cos(π/3) = 1/2.