A) 2sin^2 x - 1=0

b) 6sin^2 x + sin x = 2

c) cos^2*2x - 1 - cos x = корень из 3/2 - sin^2*2x

a)

2sin^2 x - 1=0

2sin^2 x = 1

sin^2x = 1/2

sinx = ± √2/2

sinx = √2/2

x = pi/4 + 2pik

x = 3pi/4 + 2pik

sinx = - √2/2

x = - pi/4 + 2pik

x = 5pi/4 + 2pik

b)

6sin^2 x + sin x - 2 = 0

(3sinx + 2) (2sinx - 1) = 0

sinx = - 2/3 = = = > x = (-1) ^ (k+1) * arcsin (2/3) + pik, k ∈ Z

sinx = 1/2 = = > x = (-1) ^k * pi/6 + pik, k ∈ Z